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A Newbie's Early Observation Log - Join me!

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#1 aeajr

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Posted 13 July 2015 - 10:01 PM

About a month ago I had my first opportunity to start looking at the sky. No serious plan, just me and my "guide to the stars" star wheel, a red flashlight and my 10X50 binoculars. I got in about 30 minutes of just looking around with the binos, getting a feel for them.

One thing I learned was that my eyes take a long time to fully adjust to the dark. Even as I was looking at the sky, stars seem to appear from nowhere. Even in the binoculars, as I was looking at a star it seemed like other stars were becoming more visible. Nothing much accomplished but getting my first time looking up with astronomy on my mind since 10th grade. That was over 45 years ago.


I invite other newbie astronomers to post their early observations here too so we can learn from each other and encourage each other.


FWIW. Here are the tools I have accumulated over the last 60 days to help me start in this new hobby.

10X50 Wide Angle Binoculars - $20
http://www.harborfre...lars-94527.html

Guide to the Stars
http://www.amazon.co...ATNHY55HBSGQBA9

Turn Left at Orion (Not using this yet)
http://www.amazon.co...5GN0DRQ8D13E7CT


Orion 51919 MoonMap 260 - Just ordered today
http://www.amazon.co...ailpage_o00_s00


Orion 4150 DeepMap 600 Folding Star Chart - just ordered today
http://www.amazon.co...ailpage_o00_s01


Red Flashlight
http://www.amazon.co...ailpage_o03_s00

Edited by aeajr, 14 July 2015 - 10:21 AM.

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#2 aeajr

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Posted 13 July 2015 - 10:06 PM

Saturday, July 11

I was loading some things into my car this evening, around 10:30 pm. Earlier in the evening I had looked up at the sky and saw nothing but clouds. :( But as I closed the trunk I looked up and the sky was clear as could be and I could see stars. :)

Quick, grab the 10X50 binoculars, Guide to the Stars and the red flashlight and head for the yard. I grabbed a lounge chair from the garage and tried to position myself in a way that would block all the big lights from my view. Mostly successful.

At first I just gazed up and looked at the sky. Then I used the binoculars and was amazed on how many more stars I could see. And as I held the binos to my eyes and my eyes adjusted, more stars appeared. It was quite exciting.

For about 15 minutes I just looked at random and just admired the night. Then I took out the star wheel and tried to identify some formations.

I believe I picked out Vega, almost directly overhead. As I looked at it I spotted a star pair near it. If I am correct, this was Epsilon Lyrae, the double double. With my binos I could easily see the pair but research tells me that this is really two double stars that can be split with higher magnification.

I worked with the star wheel, "Guide to the Stars" to try and positively identify the summer triangle and the constellation Lyra.

I don't know if I identified these correctly but it was so exciting to start to match up the sky with the wheel and to look for reference stars. I got lost in this for about an hour before I had to come in.

This was my first real observation where I started to identify things, picking out reference points, and it was fun! I hope I get more clear skies so I can continue to work on recognizing the stars over my head.


Strategy

My strategy for the next few star gazing sessions is to center on Vega and work my way out. Using the star wheel I would look for formations, using Vega as a reference point.

Edited by aeajr, 13 July 2015 - 10:31 PM.

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#3 aeajr

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Posted 13 July 2015 - 10:10 PM

July 13 - Star Gazing.


I stepped out my back door from my brightly lit kitchen to look up at the sky. Nothing!

Well, wait a minute, I think I see one star ... maybe a couple more. Let me step away from the house and go around the side. Oh, a few more.. oh more over there. I guess my eyes were getting adjusted and I was starting to see the stars.

I grabbed my lounge chair, my star wheel, red flashlight and my 10X50 binoculars. Let's see what asterisms I can pick out, working out from Vega.

I was facing East. OK, there is Vega high over head. I can confirm because I can see Epsilon Lyrae near by in the binoculars. So, that must be Deneb and that must be Altair. OK, the summer triangle.


Now, looking at Deneb I can make out the Northern Cross.

Back to "Guide to the Stars" star wheel. OK let's see if we can find the Great Square of Pegasus OK, it should be about over there. Ah, there it is toward the NE horizon. Good.


Let's move out in front of the house, stand in the shadow of a tree to block the street light and look up. I am now looking North.

Consult the star wheel and identify where the big dipper should be. OK, I think I got it, wait, where did it go!

Darn clouds! I had a fully clear sky for about 45 minutes then the clouds just came in and blanketed the sky.


Speed will be important


I can see that a major criteria for any telescope that I plan to use at home will be for FAST set-up and little or no temperature adjustment. So far the longest star gazing I have been able to manage has been an hour. If I have to wait for a mirror to reach temperature stabilization I would not get to see anything! Need to keep that in mind. Perhaps if I keep it in the garage rather than the house I can minimize any wait for temp adjustment.



I plan to continue my early journey in this thread and hope that some of you will comment, provide advice and guidance.

I invite other newbie astronomers to post their early observations here too so we can learn from each other and encourage each other.


I now keep the "Guide to the Stars" the binoculars and the red flashlight in the garage next to the lounge chair that I have been using so I can grab and go quickly, before the clouds roll over a clear sky.

Edited by aeajr, 13 July 2015 - 10:35 PM.

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#4 sctt50

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Posted 13 July 2015 - 10:53 PM

Just wanted to say that I've enjoyed reading your posts.  It sounds like you have a plan and (most importantly) you are having fun.  I'll look forward to hearing updates on your journey!

I also admire that you are starting with simple tools and learning the sky.  In just a few observing sessions, you're already refining your needs, also smart.

My only advice would be to join a local club.  And keep having fun!

Scott


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#5 aeajr

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Posted 13 July 2015 - 10:58 PM

Thanks for the encouragement and the advice Scott

I have located several clubs in my area. One of them is having a meeting and an observation night on Wednesday, 7/15. If the weather looks promising I may run out to the meeting. It is about a 40 minute ride.

Ed

Edited by aeajr, 13 July 2015 - 10:59 PM.

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#6 M57Guy

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Posted 13 July 2015 - 11:23 PM

Hello aeajr,

 

From one Cloudy Nights newbie to another, I’ll pass along some good advice I once received - pick up a copy of NightWatch by Terence Dickinson. It’s a great place to start for anything and everything astronomy related.

 

http://www.amazon.co...e/dp/155407147X

 

Good luck!

 

M57Guy


Edited by M57Guy, 13 July 2015 - 11:24 PM.

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#7 GaryCurran

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Posted 13 July 2015 - 11:25 PM

Well Ed, you've found yourself hooked, already.  Binoculars are a great way to explore the sky.  Here's a couple of more suggestions for you.

 

Plan your observing before you go out, so you know what to look for.  Star wheels, planispheres, are nice, but are outdated today.  Your cell phone or your computer offers so much more information.

 

For your home computer, download a program called 'Stellarium.'  It's a planetarium for your computer, and can be localized for your individual location.  It will show you all sorts of catalogs of deep space objects, some of which should be visible in your binoculars.

 

Get a camera tripod and a binocular mount, which makes it easier to hold the binoculars up for long periods of time.

 

But, we all know where this is going to lead to, and that's getting a telescope.  Start browsing the different kinds of telescopes you can get, and there are many.  The most recommended telescope for new users is called a Dobsonian Reflector, or just a Dobsonian or a 'Dob.'  They are inexpensive, pack the most 'bang for the buck', and are the easiest to use.

 

Orion Telescopes has a 'Second' on sale now:

 

http://www.telescope...ByCategoryId=81

 

Get a couple of eyepieces to go with it, and you'll not only be splitting the Double Double in Lyra, but you'll be making out the rings of Saturn, Jupiter and her moons, and several deep space objects, all for less than a good pair of Celestron astronomical binoculars!

 

http://www.highpoint...inoculars-71017


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#8 ron2k_1

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Posted 14 July 2015 - 12:07 AM

Hey there

 

Good job on logging and sharing your nightly routines. Keep a actual log of location, and objects observed and things you're noticing on that night. Describing what you're seeing. You'll be training your brain to see even more.

 

Whenever you're ready for a telescope, a Dobsonian is a good way to start. If you're used to the wide angle of the binos but want more power then save for a Refractor. The Achromatic ones are enough for now, don't go for the apochromatic ones. Those really shine when doing astrophotography. However, dobs are the ones that will cool the fastest. They will cool even faster if you get the fan pack for the primary mirror. In regards to temperature, your observing location also plays a role. For instance if you place the telescope on pave, park or driveways, rooftops, etc. Those accumulate too much heat during the day and will radiate it into the night for hours, which will get in your view path and affect your viewing. Its best if you stay on dirt or grass. Oh and you can start your preparations early, like setting up your mount and aligning the scope when there is still light in the day, so by night time your scope is acclimated and ready to point and shoot. You can keep it 'partly' covered meanwhile in case it rains and for the dew - allow for ventilation otherwise the scope will not cool down.

 

You can carry a tablet or laptop outside but use a red screen cover for it so it doesn't mess your night vision. You can also place your phone inside a red plastic bag.

 

Again, thanks for sharing. I'm enjoying your posts.


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#9 nickajeglin

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Posted 14 July 2015 - 12:10 AM

I've just started using some 7x50's to get familiar with the sky while I'm grinding a mirror. I'm lucky to be in a pretty dark area. If I drive 20 minutes from home I can see the milky way clearly. Stellarium on the phone is great, but I also printed out the star atlas from here: http://www.geocities.jp/toshimi_taki. It's laid out really intuitively and is pretty easy to use if you can get your bearings to start. So far I've been able to see M13 and M92 in Hercules (pretty easy), as well as M29 in Cygnus, (super easy to find), and M5 in Serpens (harder to find, but not difficult to see). I found most of these out of the city, but after I found them once, I can now pick them out from my porch which is covered with street lights. I had to print up some very detailed charts to find my first globular cluster, but now that I know what I'm looking for, I find I can pick a few major references, and just scan the general area until I think I see something fuzzy pop out. Then I go back to the chart to verify that the surrounding stars are where they should be. It's really exciting when you finally find what you were looking for. 

 

M13 is pretty easy to spot: if you draw a line from vega (blue white) to arcturus (very orange), smack dab in the middle, there's a keystone shape of Hercules. If you compare to a chart to find which corner to start at, and scan back and forth between eta and zeta, you'll pretty soon spot a fuzzy ball out of the corner of your eye. It makes a nice isosceles triangle with two medium bright stars.  

 

My next goal is to find M81/82, and start hunting for some open clusters, because I think they'll look nicer in the binos. The globular clusters are pretty much just big fuzzy balls, more exciting to find than to look at right now. It's also really nice to just wander around in the area of Cygnus. There are so many stars and such nice colors in there. I knew exactly what double you were talking about near vega as soon as you mentioned it, they're a strikingly beautiful pair!

 

I got one of those "zero gravity" type lawn chairs last weekend. It was a little more expensive than I would like, but it makes kicking back to look at most angles very comfortable with binoculars. 

 

Good luck, and keep us posted. I'm looking forward to following another beginner's progress. 


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#10 SeaBee1

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Posted 14 July 2015 - 08:03 AM

From one newbie to another, I am enjoying your log/posts! My wife and I just started as well, using a borrowed 6" reflector. My plan is to build a 10". I am using Sky Safari 4 on my iPhone, others like Stellarium. We are also using a logbook to record our observations and sketches. My only wish at the moment is for more time for viewing.

 

Clear skies to you and keep looking up!

 

Best regards!

 

CB


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#11 aeajr

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Posted 14 July 2015 - 08:58 AM

Thanks to everyone for your encouragement and your observation experience.


As new astronomers we struggle with things that are simple for the experienced guys. And we are all eager to buy stuff, though we really don't know what is going to work for us.

What to buy? Will my next purchase be 15X70 binoculars which should be highly portable and quick to use or will it be a telescope? What will be fast to set-up and work for short observing sessions? Not sure yet.

I am beginning to see that speed of set-up and portability may be more important to me than big aperture. That might change long term but for now I am thinking that my first telescope purchase will be biased this way.




I invite you newbies to state your plan.

How are you going to develop your knowledge and your experience?

Did you jump directly into a telescope? Has it worked out well for you? Looking back, What would you do differently?


Let's help each other as the experienced guys help us.

Edited by aeajr, 14 July 2015 - 09:53 AM.

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#12 aeajr

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Posted 14 July 2015 - 09:07 AM

My Plan

My experience from my model airplane hobby is that many newbies run out and buy the wrong stuff. As a result they fail in their early attempts, get frustrated and walk away. I don't want to be one of those.

So I am going to start with the easier stuff. I want to get to know the formations, the asterisms, that I can see with my naked eye. This will let the sky become a familiar place. Being able to share my excitement about this new hobby is important to me and this will let me do that.


I want to be able to look up and point and say to my wife or a friend, "that is Vega and there is Deneb and that is Altair. They form the summer triangle."

"Vega is in the constellation Lyra. If you look through the binoculars you can see Vega and there is a double star just to the side. You can't see that with the naked eye but you can see it with the binoculars. And, if we had a more powerful telescope that double star would actually resolve to two double stars. Cool?"

"If we look at Deneb and follow this way we see the Northern Cross."

"Over there we see the Great Square of Pegasus."

"There is the big dipper, the little dipper and there is Polaris, the North star. If we watched long enough the sky would appear to revolve around Polaris like a pivot on a globe."

I want to be able to pick out the visible planets, know where they will be in the sky and be able to find them with the binoculars.



Once I get comfortable picking out these and similar visible formations, I can start to study their major points and what is around them that may not be visible to the naked eye but can be seen with the binoculars or my old 60 mm Sears telescope that I got 45 years ago.

For example, as I looked at Vega through the binoculars I spotted the double star. A discovery! :D I didn't know that was there. That really drove home how much I could see with a $20 pair of 10X50 binoculars. It also gave me something to research as it was not shown on my star wheel. And that is an easy discovery I can show to others with simple binoculars. I now know that is called Epsilon Lyrae, the double double star. I get a gold star for that. ;)



So this is going to be a process of working from the "big" features, the visible featurs in the sky. Then I will work my way into the smaller and smaller formations and smaller and smaller features.

When I have gone as far as I can with the 10X50 binoculars then I will take the next equipment step. At that point I should be better prepared to make that larger investment. I think that will be some time around Christmas.


Will that be 15x70 binos? A 4" refractor? A 6" reflector? Larger? Go to? Push to? I don't know today. I have $$ burning a hole in my pocket but I don't really know what is going to work for me ... yet.


An important phrase I have read is, " the scope you will use most often is the one that is best for you". And, as I stated above, I am beginning to see that speed of set-up and portability may be more important to me than big aperture for my next purchase. Might be used and might be new.


That is my plan. What is yours?

Edited by aeajr, 14 July 2015 - 10:18 AM.

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#13 ron2k_1

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Posted 14 July 2015 - 01:18 PM

Man! I admire your patience and coolness to this hobby. I don't have that type of patience and self control.

 

I've been admiring the sky since, I don't know... always! When I was able to afford my first smart phone after college 10 years ago, the first app I installed was a planetarium app.  I was able to identify what was on the sky right on my 2" phone screen! I then started working and was able to afford better gadgets. But at the same time I moved from a rural town to a well-lit, almost white sky, city area.  I can only see the bright stuff - the moon, the big dipper, gemini, Orion, Vega, etc.  I struggle, and struggle, for a long time, and I've never been able to see Polaris with the naked eye in my location; although my phone is telling me, "Ron, it's right there, 17 degrees up, look!"; I'll be like, sorry, I'm squinting till my eyes hurt, I still can't see it.  It's still fun, but it sucks that your sky is limited to a hand bunch of stars and the rest is just a plain greyish white glaze washout... I do love when we have blackouts. I can go outside, lay down on steps, and look up. I can see the Milky Way bands, I can then take the overwhelming expanse.

 

So, 2 years ago we had a baby girl, and now is time to commit ourselves to our own house.  I'm the home's main provider so all my earnings goes to supporting the family. So, before, it's too late and I'm all tied up with mortgage, home construction, improvements, school fees, ballet classes, etc. I took the plunge and dropped couple thousands into 2 telescopes. A celestron advanced C9.25 (9.25" SCT) which will probably be put away for now, and a small Celestron C90 (90mm or 3.5").  The small telescope is what I'll use for my education in the beginning. Looking around with no go-to capabilities on an inexpensive altaz mount, learn where stuff is and will be at specific times.  Stretch the possibilities of the the little C90...

 

So, you may be asking why I didn't buy a pair of binos from the get go instead of 2 telescopes.  Well, I read a lot, and have a huge amount of theory already pat down (I had to somehow satisfy this urge without having any equipment and clear skies...).  And from my readings I realized that I'd like to watch the planets at sizes bigger than just pin heads.  In the area of binos, that will require at least 100mm of aperture. But those cost over $300.  So I decided for a small telescope I can use at night for newbie astronomy and day time when birdwatching with my daughter's seasonal exploring urges.  That's how I arrived at the C90.  Why not a small 80mm or 100mm achromatic telescope then? Because I'm stupid, that's why.  The theory didn't explain to me quite well that long focal point = tiny FOVs.  But, education has it's cost. In my case, the cost of a telescope I'd probably only have for few months. "And why did you buy an enormous 9.25" Schmidt Cassegrain?", you may ask.  Well, this was a impulse purchase. That's where you and I are very different. I saw the telescope in pristine condition on ebay, being sold by a guy who got disabled after purchasing it, at a HUGE discount.  I had the cash now, which I may not have in a year's time. So here I am - 0 practical experience, countless megabytes and hours of theory stored in my head, 2 telescopes that I'll pick up tomorrow.  I like hanging with an executive of the bank I currently work for.  He has a 5" Mak, which I've been allowed to touch every now and again.  But it's not like owning your own scope.  This guys insists on telling you how to the scope works, and the history of it, and the little (in my opinion) he knows about the sky that we don't really use his telescope...  And you'd assume he would remember he already told you all those things when you comeback to his house...

 

So here is my plan:

1. Slap the C90 on the alt-az mount.

 

2. Use a planetarium star wheel with a red light (I don't want to use my phone or a tablet and spoil the dark adaptation I can hardly achieve in my location).  I've read that people use an eye patch to cover their observing eye and only use their uncovered eye to answer calls, look at their star charts on their phones or laptops.  That sounds so uncomfortable to me. So I'll stick with paper.  If I can find (or allowed to take) the time to go to a dark location 20-25 miles out, then I'll bring my phone in a dark red plastic bag.

 

I'll probably do this for the next year or so.  Bringing out the mighty C9.25 every now and again for detailed view of the planets and few DSOs.  After all, I did buy several 2" super wide angled eyepieces and several color/contrast lens filters.  They need to have use.  And it may be refreshing to just relax and observe exactly what you want rather than enduring constant headaches when you can't find your way around with manual slewing.

 

I'll start a log, with pictures taken by cell phone held to the eyepiece and some sketching.  Training the eye to see more and more every day.

 

In one year or sooner, I'll probably replace the C90 with a 100 mm doublet achrom telescope.  It will still serve the day time exploring, solar observing, and wide FOV night watch.  Again, on a manual mount.  With time, I can probably dabble into astrophotography by placing the achromatic on the CG-5 GEM mount (that came with my C9.25O) and purchasing a small CCD camera.

 

Down the years, when the house is all completed and finances are again balanced. I'd like to build a small observation hut that can house a 12 or 14" Dob.  By then I should have some limited skills of moving around the sky, and probably amassed several high quality eyepieces and other goodies.  So the expense then will not be as crippling as it was 2 weeks ago.


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#14 aeajr

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Posted 14 July 2015 - 01:54 PM

ron2k_1

Great report!

I fully understand those impulse buys. I have looked on Craig's list and there are a bunch of scopes all around me that might be of interest, but I am going to force myself to hold back.

Sounds like the executive of the bank would probably like to hang around with you and your 9.5" CST. Then you can tell him all about it. :) You should set up play dates for your scope and his. :D


If I had a 9.5 CST you could bet I would not be stuffing it in a closet. When the price is too good, you have to go for it. So now that you have it, use it.


That C90 should really help you find more things in the sky. Even with the 10X50 binoculars I can see so much more than I can with my naked eyes. If you feel the C90 is too narrow a view, get a pair of 10X50 binoculars. Mine cost $20 and work great! Use the Binoculars to find the object then use the C90 or the 9.5 CST to focus in more closely!

In the light polluted sky of Long Island, East of NYC, Vega is a single point of light and I can only dream of seeing the Milky Way. But if I look at Vega, a single point of light in the sky with nothing around it, through the binoculars, there is a whole bunch of stars there and the double star I mentioned above, Epsilon Lyrae. I find that double star to be so cool!

And I have found that to be true for each of the stars I have looked at. A single spot of light in the sky, but in the 50 mm binoculars that pin of light is sitting in a sea of stars in the wide angle view of the binoculars. Just seeing that has been exciting. There is so much up there that I have never seen before.

I have a 60 mm telescope but the view is very narrow. I find, at this stage, that I prefer the wide angle of the binoculars compared to the narrow view of the telescope.

I have looked at the moon. Cool. Just ordered a moon map. Have not tried for any planets yet.


Good luck with your new telescopes and be sure to post some observation reports.

Go find Polaris! :D

Edited by aeajr, 14 July 2015 - 02:02 PM.

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#15 GaryCurran

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Posted 14 July 2015 - 02:25 PM

An important phrase I have read is, " the scope you will use most often is the one that is best for you". 

 

Well, let's start off with this.  You read it wrong.  It's important that you read it correctly, because it's not something you can just flip around.

 

'The best scope for you is the one you use most often.'  There's a difference, albeit subtle.  If you only have one telescope, and it's a 60mm Department store AltAz, and you use it often, it doesn't mean it's the best scope for you.  You might get something that's bigger in aperture, and a little less portable, but you find that you use that more often, then that's your best scope.  Then again, if you have a short focal length refractor, costing the better part of $2,000, and you want to view planets, a Maksutov Cassegrain reflector that costs $400 might be the better scope for you, and you'll use that more often for planets.  You certainly wouldn't use a short FL refractor for planets.

 

So, if you only have ONE telescope, obviously that's the best one for you.  But, the statement is usually referenced to those with two or more telescopes.  However, a telescope and a pair of binoculars can be considered 'more than one telescope.'

 

Now, you talked about portability, which is why I earlier recommended the 4.5" Dobsonian.  Very easy to carry and set up, it can be taken into your backyard and set up in a matter of minutes.  The nice thing about it is you have control over the magnification, just by selecting a different eyepiece.  You also don't have to worry about your arms getting tired from holding your binoculars all evening, even if you are reclining in a special chair.  It's easier to share views with others, since the telescope is already pointing at your target, and you don't have to point out the target in the sky and hope they can figure out what you're talking about.

 

No doubt, binoculars are good for star gazing, are quick and easy, but a small Dob has it's own appeal, also.


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#16 aeajr

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Posted 14 July 2015 - 02:49 PM

GaryCurran

Great points.

 

My comments about the scope I would use the most was related to set-up time and portability only.   Says nothing about what technology.  I don't know enough about that yet.

 

So let's discuss that 4.5" dob. Is there a cool down/warm up period for something like that? Any feeling for how long that might be, on average? And don't those need to be aligned before you use them?

 

"Then again, if you have a short focal length refractor, costing the better part of $2,000, and you want to view planets, a Maksutov Cassegrain reflector that costs $400 might be the better scope for you, and you'll use that more often for planets. You certainly wouldn't use a short FL refractor for planets."


Great info but I dont' understand it.  Explain to me why I would want a Mak Cass for planets rather than a short FL refractor? And what would you consider short FL? 700 mm? 1000 mm?

 

If a refractor is not good for planets then what is it good for?  

 

you mentioned a Mak Cass for planets.  Does that mean that I would not use a 4.5" dob for planets?  So, what would I use the Dob for?
 

Is field of view a decision point for these scopes or do they have similar FOV characteristics?

 

I have been reading like crazy but I have not internalized any of it yet.   This is one of those areas that tells me I am not ready to buy anything yet. I understand binoculars sufficiently to know why to go to a 15X70 and roughly how that would compare to my 10X50s.  So that is a safe move from that point of view, but does it take me where I want to go?   I don't know.

 

Any decision will be a compromise, I understand that.  But I don't understand what the decision points are.

So, I don't understand your statements about telescopes. I would need to understand in order to know what to buy and why. And how would a 4.5" Mak Cass relate to a 4.5" SCT to a 4.5" Dob. 

 

I don't see many moderately priced refractors over 100 MM, about 4",  so let's assume reflector above that. 

 

Where does each fit in, from a view and use case point of view?  If I buy one that is good for planets then can I not use it for stars and clusters and galaxies?

 

And what about Goto?  My understanding is that SCT and Mak Cas have a lot of go to options, but no so much with Dobs.

 

I want to look at all of it.  I want to see the planets, the moon, stars, clusters, galaxies and all. I likely can't afford, nor do I have a place to store 3 telescopes of significant aperture so how do I select and what is the best compromise?  If I make a mistake and can't view the sky I am going to be very bummed out.  :(

My inquiring mind wants to know.


Edited by aeajr, 14 July 2015 - 03:00 PM.

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#17 GaryCurran

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Posted 14 July 2015 - 02:59 PM

Ron,

You will be amazed at what the little 90mm Mak is going to show you.  Now, I'm not exactly sure which one you got, is it a new one, or a used one?

If you got the new one, it's a black tube scope, right?  Comes with a 32mm eyepiece?

 

That little telescope looks like it has a 1250mm focal length.  It should give you great views of Jupiter, Saturn and Mars, and many DSOs.  On a little AltAz mount, you should be able to find a lot of stuff and enjoy that scope.  Plus, the price is pretty good, at $230 or so.  In fact, at some point in the future, I plan on adding it's bigger brother/cousin, the 127mm.

 

http://www.highpoint...cope-ota-s11520

 

I believe these are all made by Synta.  My first telescope was the Orion 127mm Mak Cass, and I greatly miss that scope.  For planetary and Lunar, these are just great.


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#18 Tony Flanders

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Posted 14 July 2015 - 03:20 PM

I believe I picked out Vega, almost directly overhead. As I looked at it I spotted a star pair near it. If I am correct, this was Epsilon Lyrae, the double double. With my binos I could easily see the pair but research tells me that this is really two double stars that can be split with higher magnification.

My strategy for the next few star gazing sessions is to center on Vega and work my way out. Using the star wheel I would look for formations, using Vega as a reference point.

Almost certainly Epsilon. Zeta Lyrae, the third star of the tiny triangle with Vega, is also a double. But it's tough to split with handheld 10x binoculars, whereas splitting Epsilon into two stars is a piece of cake.

 

Take a look at Delta, the third star near Zeta. It's actually a mini-cluster.


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#19 Tony Flanders

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Posted 14 July 2015 - 03:29 PM

Let's discuss that 4.5" dob. Is there a cool down/warm up period for something like that? Any feeling for how long that might be, on average? And don't those need to be aligned before you use them?


The cooldown period depends on the temperature differential and how much magnification you want to use. At low magnification, the scope will deliver far more detailed views than your binoculars as soon as you bring it outside.

If you want to see details in Saturn's rings at 100X, you may have to wait a while.

As for collimation, yes it's a good idea in theory. But to be perfectly honest, I often use my small reflectors without so much as checking the collimation, let alone tweaking it. They stay collimated pretty well unless you drop them -- and sometimes even then. (Yes, I speak from experience.)

For instant availability and versatility, nothing beats a small refractor. But at a price.

In your situation I think it makes much more sense to get a small scope -- any decent small scope -- than 15x70 binoculars. 15x70 binoculars certainly have their place, but any decent telescope will show you all kinds of things that are difficult or invisible at 15X. Saturn's rings alone are worth the price of a telescope.

Edited by Tony Flanders, 14 July 2015 - 03:49 PM.

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#20 ron2k_1

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Posted 14 July 2015 - 04:10 PM

@aeajr

 

Dobs, Maksutov and Schmidt Cassegrain are all long focal length (FL) telescopes.  These provide high resolution images and are made for high power (high magnification) views.  The difference between Dobs and Catadioptric (Maks and Schmidt) is that the latter pack the same FL in a compact form.  Take for instance my C9.25 with 9.25" aperture packing an FL of 2350 mm.  To have that much focal length in a Dobsonian at a focal ratio of F5, the scope will need to have an enormous aperture of 18.5 inches (2350/5/25.4)! Well over 200 lbs in weight compared to the 20 lbs optical tube in the C9.25.

 

So, how is this different to Refractors? Refractors are generally very fast telescopes [focal ratios of less than 6].  The lower the focal ratio, the wider the field of view (FOV).  You calculate FOV, by dividing the FL of the telescope by aperture in mm.  In my C9.25 is 2350/235 = F10.  A 16" Orion Dobsonian has a FL of 1800 and aperture of 400 mm (16 inch x 25.4) = F4.4. So why is this relevant?  Let's say you have only 1 eyepiece: a 32mm 52 deg Plossl; and you have 3 telescopes: A 100mm F6 Achromatic, XT8" F5 Dobsonian and the Celestron C9.25 F10 Schmidth Cassegrain Telescope (SCT).  Your magnifications with the provided 32mm will be: (600mm FL/32)=18X, (1000/32)=31X, (2350/32)=74X respectively for each telescope [FL in mm for each telescope is Aperture x Focal Ratio].  Your magnification is a mathematical calculation of FL of Telescope divided by FL of eyepiece.

 

Now, you FOV is calculated with the formula of FOV of eyepiece divided by Magnification. So in your case with the 32mm 52 degree Plossl your FOV on the 3 telescopes are: (52/18)=2.9 degrees (similar to your binos), 1.6 degrees, and 0.7 degrees respectively.  So as you see, the smaller the FL, the larger the FOV.

 

Now, why does that matter? Look at Andromeda. It is 3 degrees wide in the sky.  No matter which eyepiece I use on my Celestron C9.25, I'll never be able to fit the whole in the FOV.  But with a 100mm F6 Achromatic I can simply use a 40mm 52deg plossl and have spare space in the FOV (600/40 = 15x magnification and 52/15 = 3.5 deg FOV).  That same 40mm eyepiece can give me 25X magnification and 2 degree FOV on the 8" Dob. 

 

So we conclude that for galaxies (big objects) we are better off with an apochromatic.  But what about planets?  Now let's assume that your lowest FL eyepiece in your collection is 5mm.  This can give you 120X mag on the Achromatic and 470X on the C9.25.  FOVs would be 0.43 on the Achromatic and 0.1 deg on the C9.25.  Bear in mind that Jupiter when nearest to earth is around 50 arcsecs or 0.014 degrees.  So on the C9.25, the planet will fill more than 10% of the scope, but on the Acromatic will look very very tiny.

 

So, a good observer kit should have one of those sweet Achromatic (for best results: a triplet apochromatic) and a long FL telescope (a dob for instance).


Edited by ron2k_1, 14 July 2015 - 04:14 PM.

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#21 GaryCurran

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Posted 14 July 2015 - 04:10 PM

GaryCurran

Great points.

 

My comments about the scope I would use the most was related to set-up time and portability only.   Says nothing about what technology.  I don't know enough about that yet.

 

So let's discuss that 4.5" dob. Is there a cool down/warm up period for something like that? Any feeling for how long that might be, on average? And don't those need to be aligned before you use them?

 

"Then again, if you have a short focal length refractor, costing the better part of $2,000, and you want to view planets, a Maksutov Cassegrain reflector that costs $400 might be the better scope for you, and you'll use that more often for planets. You certainly wouldn't use a short FL refractor for planets."


Great info but I dont' understand it.  Explain to me why I would want a Mak Cass for planets rather than a short FL refractor? And what would you consider short FL? 700 mm? 1000 mm?

 

If a refractor is not good for planets then what is it good for?  

 

you mentioned a Mak Cass for planets.  Does that mean that I would not use a 4.5" dob for planets?  So, what would I use the Dob for?
 

Is field of view a decision point for these scopes or do they have similar FOV characteristics?

 

I have been reading like crazy but I have not internalized any of it yet.   This is one of those areas that tells me I am not ready to buy anything yet. I understand binoculars sufficiently to know why to go to a 15X70 and roughly how that would compare to my 10X50s.  So that is a safe move from that point of view, but does it take me where I want to go?   I don't know.

 

Any decision will be a compromise, I understand that.  But I don't understand what the decision points are.

So, I don't understand your statements about telescopes. I would need to understand in order to know what to buy and why. And how would a 4.5" Mak Cass relate to a 4.5" SCT to a 4.5" Dob. 

 

I don't see many moderately priced refractors over 100 MM, about 4",  so let's assume reflector above that. 

 

Where does each fit in, from a view and use case point of view?  If I buy one that is good for planets then can I not use it for stars and clusters and galaxies?

 

And what about Goto?  My understanding is that SCT and Mak Cas have a lot of go to options, but no so much with Dobs.

 

I want to look at all of it.  I want to see the planets, the moon, stars, clusters, galaxies and all. I likely can't afford, nor do I have a place to store 3 telescopes of significant aperture so how do I select and what is the best compromise?  If I make a mistake and can't view the sky I am going to be very bummed out.  :(

My inquiring mind wants to know.

 

Okay, let's go through this from the beginning.  Almost every telescope, and even binoculars, require a period of thermal stabilization.  The larger and more complex the telescope, usually, the longer the stabilization requires.  Mirrors and glass optics need to have time to stabilize, and obviously, the larger the mirrors and optics, the longer it will take.  You also need to take into account the temperature difference.  Say you got a Dob, and left it in the garage, properly covered.  There wouldn't be any need, since it would already be at ambient temperature.

 

As to 'aligned', do you mean collimated?  Collimation is the proper alignment of the mirrors to make sure everything is 'on axis.'  You may need to collimate it once in a while, but if you're careful, not every time.  Some observers collimate every session, and it takes three or four minutes to do, others don't unless things are really bad.  More for astrophotography than casual visual observation.  I never collimated my first telescope, a 127mm Mak Cass.

 

Telescope Design and Magnification.

If you look through your binoculars at a star, or if you look through the most powerful visual telescope on earth, you're going to see the same thing, a white pinprick of light.  Unless you're looking at Sol, you'll never see a disc.  In the universe, stars are pretty small objects, and of course, planets, even smaller.

 

Now, the basic rule for magnification says the focal length of a telescope divided by the focal length of the eyepiece equals the magnification.  So, a 1,000mm telescope using a 25mm Eyepiece will give you 40 times magnification.  The same telescope with a 10mm eyepiece will give you 100x magnification.  However, as you increase magnification, your target will become dimmer.  For planets, which are very bright objects in the sky, this is not a problem.

 

Download the free program Stellarium.  In it, there is something called the Ocular Plug In, and it allows you to simulate the view (although not the brightness) of a telescope and eyepiece combination.

 

Now, as an example, I have an older 80mm refractor telescope.  Refractors are the 'classic' telescope, long tube, and you look in the end of it.  The 80mm refers to the diameter of the 'objective', the same as the 50 refers to the size of the objective in your binoculars.  My telescope, therefore, is about 3.1" in diameter.  The 'focal length' is the distance the light is refracted before coming into focus at the end of the tube.  So, let's take Saturn, which is still in the summer sky.

 

With a common 25 or 26mm eyepiece, I'll be able to see two very close dots, next to each other.  One is Saturn, the other it's larger moon Titan.  If I'm lucky, I may make out a slight oblong shape to Saturn, which denotes it's rings.  I also might see a couple of other dots, which would be other moons.

Switching to a 10mm eyepiece, there might be some distance now between Saturn and her moons, and you might see Saturn and four or five other dots, her moons.  If I move to a 6mm eyepiece, and the viewing is very good, I may start to see the actual rings, and the space between the rings and the planet.  About the best I can expect from that scope would be with a 4mm eyepiece, and I should be able to make out several of Saturn's moons and her rings, but she will still be very small on the eyepiece.  This is about 200 power.

Now, if we switch telescopes to, say a 127mm Maksutov-Cassegrain, with a 1,500mm focal length, Saturn will still be small in the eyepiece, but using that 4mm eyepiece, we'll push the magnification up towards 350x magnification, and her moons will show nicely, and the rings will, or should be, nice and clear.  You may even, upon close inspection, see the Cassini division in the rings.  Saturn, still though, is going to be a little dot, and won't be filling your eyepiece.

Now, if you have an 8" Schmidt Cassegrain, with a 203mm aperture and a 2,032mm focal length, you MIGHT, on a really good night of seeing, be able to make out the inner moons of Saturn, details in the ring structure, and even some of the banding on the planet, by using a good 2-3mm eyepiece.

When I originally spoke of a 'short focal length' telescope, I was talking about one in the 400-500mm focal length range.  I would not reasonably expect to be able to use anything smaller than a 6 or 7mm eyepiece, so Saturn would be nothing more than a larger dot, with a few smaller dots around it for her moons.  No rings or anything like that.

 

But, that's not what the design is supposed to be used for, either.  Small refractors like that are designed for wide field observing.  The Andromeda Galaxy is almost 3° in width, six times larger than our moon!  With that same small refractor and a 26mm eyepiece, I can fit the entire Andromeda Galaxy into view, at about 16 power.  I could fit either the Heart Nebula or the Soul Nebula into the field of view with a 26mm eyepiece, but not both together.

Using the aforementioned 127 Mak, the Soul Nebula overflows even my widest eyepiece of 32mm.  The Andromeda Galaxy I can only see the center half of the galaxy.

 

So, you can see that there are different telescopes for different objects in space.  What is good for lunar and planetary viewing is too much for many Deep Space Objects, and what is good for DSOs may not even allow you to notice a planet as a planet.

 

A refractor may be very good for planets, I've seen some wonderful views of Saturn from a refractor, but as there are different sized scopes, so it applies to refractors as well.  Remember that focal length of the telescope divided by the focal length of the eyepiece equals magnification.  So, if you had a refractor of 1,500mm focal length, it would give you the same magnification as the Mak-Cass we discussed earlier.

 

Here is a refractor that also has a 1,500mm focal length.

 

http://www.highpoint...actor-telescope

 

Notice that the length of the telescope is almost 5 FEET long.  In comparison, here's that 127 mm, 1,500mm focal length Mak Cass.

It's 13" long.

 

http://www.highpoint...cope-ota-s11520

 

Also, notice the price difference.  Same view, just two different ways of getting there.

 

As to using a Dobsonian for planets, you can.  You can use it for anything you want, with the same limitations.  Your focal length determines magnification.  The 4.5" Dob also has the same focal length as my old achromat refractor, 900mm.  But, it has an inch and a half more aperture, so you will get more light, and more detailed views.  It'll be the same size in the eyepiece, but you'll get more details.  That accounts for a lot.

 

As to FOV, that is dependent on both of your telescope and your eyepiece.  Even changing eyepiece design will change your FOV for the same telescope.  There are calculators for that.

 

As to your lack of knowledge, this is why Cloudy Nights is such a great place, you will get so much information and so many points of view and so much information that you will, when you're ready to buy a scope, know exactly what you want.

 

Everything is a compromise, unless you're really rich.  Most people, you will find, have more than one telescope.  But, the nice thing is that for many of them, one single mount can be used, and then the telescope that's best for that night's planned viewing can be used.  But, they aren't all the size of that Dobsonian, either.
My collection began last year when I bought a mount to do astrophotography, and all I planned on doing was using the mount and my camera, didn't care about the telescope.  Well, the telescope came with it.  I still have the scope, the mount was garbage and didn't last, nor did it work properly.  Now, I have a new mount, and also a larger telescope, so I have two scopes now.  I'll also have a smaller, third one in a couple of weeks.  That's where I'm drawing the line for a year or so.  :)  Each one will be for a specific purpose.

 

However, in my opinion, the best starter scope, for someone who is just getting into telescopes, is a Dobsonian Mount Reflector telescope.  They are easy to use, provide startlingly good views of a number of objects in the night sky.

 

This image was taken with an 8" Dob.

 

http://www.astrobin.com/73143/

 

Here's Mars, taken with a 6" Dob.

 

http://www.astrobin.com/86237/

 

This is the Orion Nebula taken with an 8" Dob.

 

http://www.astrobin.com/146641/

 

Feel free to ask questions of this community, they are a good bunch of people here, and will answer what may seem to be the silliest questions, because they know they aren't silly.


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#22 ron2k_1

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Posted 14 July 2015 - 04:20 PM

Oh, GarryCurran,

 

Yep, I have one of the modern C90s.  I did considered the 127mm Mak as well, but I would have been too heavy for terrestrial use with my daughter (in her case I have to carry water, food, snacks, diaper, tower, umbrella, different eyepieces as there is no zoom on these telescopes unless you have one of those zoom eyepieces).  So I opted for the C90.  It was cheaper than that at $149 new from amazon with Prime shipping. The Alt Az mount cost 60 bucks and from the reviews it's very solid and recommended (even by the manufacturer) for the C90.  I'll have fun...

 

If I had really internalized all that I just said on my previous post, I would have probably gone for an achromatic telescope. I've seen doublets for $200 bucks which was just $50 more than the C90. I was already going to have the C9.25 anyways... But such is the cost of education as I said earlier.

 

Ron


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#23 aeajr

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Posted 14 July 2015 - 04:51 PM

Tony, Ron and Gary,

 

You guys are great.   I have seen all of that info before but you helped to pack it all into one space and make it very understandable.  Thanks so much.

 

Seabee, Nick, Scott, M57,

 

Glad you joined the discussion and have shared your insights and views.  Please keep adding.

 

I look forward to other newbies joining the discussion, learning from your posts and sharing their observations.

 

This is going to be fun!

 

Ed


Edited by aeajr, 14 July 2015 - 04:54 PM.

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#24 aeajr

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Posted 14 July 2015 - 08:16 PM

I have done some research around the topics that you provided above. The thing that confused me was how you associate a given FOV and mag or use case to a specific telescope construction; refractor, Dob, SCT, Mak and so on.    I could not follow it as I did not understand the design goals of each construction while these are obvious to you.

 

So I have tried to take it down to its basic formulas and consider them in the general case rather than a specific scope construction.

If I understand the formulas, it is really independent of the telescopes construction and more around the radios of focal length of the scope, focal length of the eye piece and the aperture.   On these three the design goals are set and the compromises made.
 

Magnification = focal length of scope/focal length of the eye piece

 

As magnification increases brightness of image decreases for constant aperture limiting the practical magnification.

 

The lower the focal ratio, FL/aperture,  the wider the FOV. An F5 will have a wider FOV than an F10. 

 

So, if I want a wide view I look for a scope that has a low focal radio. (a fast scope) something around F5. ( Good for large objects, galaxies for example, or the Moon perhaps)
 

If I want to see the object larger in the eyepiece I go for a high focal ratio, smaller FOV, say F10  (Good for planets for example)

 

If I want high mag I want something with a long focal length.

If I want a bright image that can stand up to high mag then I need a large aperture.

 

These ratios also produce the lowest and highest practical magnifications for a given scope.

 

In the computer business we say that you can have good, fast, and you can have cheap. But you can only have two at a time at a reasonable price. You can have all 3 but you pay dearly for it.

 

So it is in telescopes. You can have bright, high practical magnification and a convenient size.  You can have wide FOV or you can have large objects in the lens but you can't have both.    Try to ge them all in the same scope and you will pay dearly for it or have a scope that is so big it is impractical for the amateur astronomer.  So there is always a compromise and a design goal to consider.

How am I doing?


Now, understanding the compromises, we look at the various constructions and see which features this design has been optimized to.  This will tell us the best use case for that design.

Do I have that right?

 

From this it becomes apparent which construction, which scope type, is optimized to which kind of viewing, which use case and what we can expect to see when we look in the eye piece.
 

 


Edited by aeajr, 14 July 2015 - 08:26 PM.


#25 Tony Flanders

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Posted 14 July 2015 - 09:16 PM

If I understand the formulas, it is really independent of the telescopes construction and more around the radios of focal length of the scope, focal length of the eye piece and the aperture.   On these three the design goals are set and the compromises made.


Yes, that's precisely correct. You can buy eyepieces of many different focal lengths, so the things that matter with the telescope are the aperture and its focal ratio (f/ratio). The focal length can be computed from those two numbers; it's just the aperture times the focal ratio.

However, this isn't entirely independent of the design, because different designs have different characteristic focal ratios. For instance, Cassegrains of all sorts (SCTs, Mak-Cas's, and the relatively rare classic Cassegrain) have inherently long focal ratios, so they're inherently limited in field of view.
 

The lower the focal ratio, FL/aperture,  the wider the FOV. An F5 will have a wider FOV than an F10.


More precisely, the wider the maximum field of view. You can increase a telescope's field of view by using an eyepiece with a longer focal length or a wider apparent field of view. But both of those increase the physical size of the eyepiece, and ultimately you reach the limits of what's possible in the given barrel size, which is usually either 1.25 or 2 inches.
 
Note that the focuser size -- 1.25 inches versus 2 inches -- is also a major factor here. An f/8 scope with a 2-inch focuser has roughly the same maximum field of view as an f/5 scope with a 1.25-inch focuser. But to achieve that field of view you need 2-inch eyepieces, which tend to be costly.
 

So, if I want a wide view I look for a scope that has a low focal radio. (a fast scope) something around F5. ( Good for large objects, galaxies for example, or the Moon perhaps).


Mostly good for browsing large chunks of sky -- as with your binoculars -- and for viewing large star clusters such as the Pleiades. There are only two galaxies in the northern sky that are big enough to be a problem, and the Moon will fit handily in the field of view of any but the biggest scopes.
 

If I want to see the object larger in the eyepiece I go for a high focal ratio ... and long focal length.


Not necessarily! Some of the best high-power scopes have short focal ratios. For instance, my 12.5-inch f/5 Dob is a superb planetary scope.

What you do is simply use an eyepiece with short focal length to achieve the same magnification. Or, cheaper, a Barlow lens, which effectively increases the scope's focal ratio.

So anything a long-focal-ratio scope can do, a short one can do also, but not vice versa.

The only problem is that scopes with short focal ratios tend either to have bad aberrations or be very expensive to produce. That's particularly true with refractors, which all suffer from false color to some degree. The false color is inversely proportional to the focal ratio, so f/4 refractors have twice the false color of f/8 refractors with the same design.

That's the reason that inexpensive short-focal-length refractors aren't great for planets -- not because you can't achieve high magnification (you can) but because of their false color.
 

If I want a bright image that can stand up to high mag then I need a large aperture.


Right. Aperture is by far the most important aspect of a telescope, assuming that the quality is decent. It determines both how much you can magnify and how faint you can see.

 

But obviously big apertures cost more and weigh and bulk more. They also have smaller maximum fields of view, because there's a limit to how short you can usefully make the f/ratio. My 12.5-inch f/5 Dob is great for viewing galaxies, but not for the Pleiades.


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