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Beginner - Celestron 8se

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#1 willwill

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Posted 22 September 2020 - 12:59 AM

I started out just looking around the sky, mostly was just messing around with it, while feeding all the mosquitos here on my lake,but  couldn't get mars nor jupiter or saturn, to focus at all. Thank god i ordered starsense, because getting that thing to align with my data was a PITA. In fact, i never did, I just decided to browse the sky for an hour or so, while battling the mosquitos lol. Fun times, it can't get cooler soon enough here in florida, but don't worry the mosquitos still bite here on the lake when its cold out. So, that will be fun. I had a travel telescope i messed around with, and for the most part tonight, that telescope seemed similar views of mars/jupiter... eg... they just look like circles that are kinda blurry unless i zoom way out, After i install star sense camera tomorrow night, i'll take it out and give it a better go since it'll be aligning itself, and then it'll only be user error or eyepiece error that keeps it from looking like it should.Which i am aware is not perfect unless stacking images etc.. But, i should be able to make out saturns rings with a stock Plossl 25mm piece no?      For now, my setup is as follows. 

 

Celestron 8se 

2 inch Diagonal, with the 25mm stock 1.25 in the attachment for it.

I do have a focal reducer on order  

Celestron - StarSense AutoAlign - will be here tomorrow

A dew warmer, because it's muggy as anything here. 

t ring and t adapter for when i want to connect our t3i canon, assuming i ever get a view!

Battery pack

 

Question : I ordered a 2 inch diag. from celestron, I'm supposed to remove the stock pieces and then attach it directly to the back of the telescope? i think that's the only way it'd work anyway. Not, sure why i bought the 2inch at this point since i dont have any 2 inch eye pieces, but shrug.. i heard it was better than stock and really good quality.

 

i did not do any focusing etc.. before i took it out, i just took it out. Tomorrow i'll work on that long range focusing test i see others talking about.  Perhaps mars is always supposed to be the size of a ball point pen in the lens, if so maybe that's my issue. I'm in my mid 40s and my eyesight isn't what it used to be.  alas, i try tomorrow again.



#2 Napp

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Posted 22 September 2020 - 01:20 AM

Congratulations on the new scope!  Focusing an SCT can be a chore the first time.  You may have to turn the focuser a lot.  But at the same time you have to go slowly or you might pass the focus point without noticing.  If you only have a 25mm eyepiece you are using less than 100X to observe with.  That's not much when it comes to observing Mars.  You really want a magnification closer to 200X or more if possible.  You mentioned a focal reducer.  That will reduce magnification further.  You need an eyepiece that will produce about 150X and another that produces about 200X for planetary observing.  With a scope focal length of 2000mm that would mean eyepieces of about 12 to 13mm and 9 to 10mm.  The sky usually limits magnification to about 200 to 250X.

 

You don't really need a 2 inch diagonal if you don't have any 2 inch eyepieces.  Going to wide angle 2 inch eyepieces would eliminate the need of a focal reducer unless you plan to do photography of larger targets..  You will get a better view with a quality 2 inch wide angle eyepiece than a focal reducer anyway.


Edited by Napp, 22 September 2020 - 01:27 AM.


#3 willwill

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Posted 22 September 2020 - 02:09 AM

Congratulations on the new scope!  Focusing an SCT can be a chore the first time.  You may have to turn the focuser a lot.  But at the same time you have to go slowly or you might pass the focus point without noticing.  If you only have a 25mm eyepiece you are using less than 100X to observe with.  That's not much when it comes to observing Mars.  You really want a magnification closer to 200X or more if possible.  You mentioned a focal reducer.  That will reduce magnification further.  You need an eyepiece that will produce about 150X and another that produces about 200X for planetary observing.  With a scope focal length of 2000mm that would mean eyepieces of about 12 to 13mm and 9 to 10mm.  The sky usually limits magnification to about 200 to 250X.

 

You don't really need a 2 inch diagonal if you don't have any 2 inch eyepieces.  Going to wide angle 2 inch eyepieces would eliminate the need of a focal reducer unless you plan to do photography of larger targets..  You will get a better view with a quality 2 inch wide angle eyepiece than a focal reducer anyway.

I see,  Thanks for the tips. I try to stick to amazon because they have free returns. Any suggestions? I'm already in the mid 1k's, wanted to save some things for christmas time since my girlfriend never knows what to get me. But, if i need it now, heh i need it now, much like the starsense, glad i bought it. I don't have the patience with the ole mosquitos!   I have the focal reducer in case i do, some picture taking stuff later on. 

 

How does this one look?  https://www.amazon.c...5149aa9081&th=1

 

or maybe a zoom eyepiece. I think for now ,i'll stick with the 1.25 and then go from there. i'll hold onto this 2inch angle for now. I just wish i had lowere than the 25mm right now for planets, hmm, i'll check around 


Edited by willwill, 22 September 2020 - 02:19 AM.


#4 barbarosa

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Posted 22 September 2020 - 03:31 AM

The Celestron f/6.3 Reducer Corrector for C Series Telescopes does two things for you. Note that the product name says "Reducer Corrector" because the it does two things. It reduces the focal length from ~f/10 to ~ f/5.3 and it corrects some of the aberration  that is inherent in the standard SCT design. You get a faster scope, a wider field and a flatter field with better looking stars. It is not a perfect corrector but the improvement is noticeable.  The third benefit is that the f/6.3 works well with both eyepieces and cameras.

Is this better than just buying a long focal length EP?  That I can't say because it comes down to each person's preference and the characteristics of the particular eye piece involved.

 

An SCT is not a widefield design, and some long focal length EPs are uncomfortable for some people, others love 'em, but nothing can make the field of view wider that the design allows. Astronomy Tools has an excellent field of view calculator, you select your scope, an EP from the list, or add it as custom EP, add in if you wish a Barlow or a reducer, select an object from the list and you get a preview of how that object will appear  (in terms of size in the EP). You can directly compare different EPs and reducer combinations.

 

The Plossl is a good basic EP design, but the eye relief, how close your eye must be to the exit lens, gets shorter as the focal length decreases. ER for a 4mm Plossl is about 4-6mm, glass to eyeball and the exit lens is small. 

 

When I had an 8 SE never once was the seeing good enough to allow the use of a 4mm eyepiece for any planet. Once or twice on the moon, but that was about it. 12 to 25mm was the usual range and a few times an 8mm, a very few times. I also liked and often used a zoom EP,  Vixen, Tele Vue and a Celestron. The Celestron was a good performer at a much lower price. Orion has a $60  zoom and some at 2 or 4 times that amount.

 

For planetary work consider the Orion Edge On Planetary eyepieces, Orion is not the manufacturer and you may be able to find the same model at a lower cost. The one that I tried was pretty good and had very good eye relief.

 

Don't buy a set. Consider Barlows.


Edited by barbarosa, 22 September 2020 - 03:33 AM.


#5 MrRoberts

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Posted 22 September 2020 - 09:14 AM

My 17mm rarely leaves my C-8 (w/fr).Only on those rare occasions when the atmosphere allows have I ever used my 8mm.

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#6 willwill

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Posted 22 September 2020 - 10:33 AM

So a 4mm would be way too small ? 



#7 PNW

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Posted 22 September 2020 - 12:23 PM

As a rule of thumb I use the focal ratio = eyepiece focal length. On my f/10 SCT that would be a 10mm eyepiece is the maximum useful magnification. I can tell you I use my 12mm eyepiece far more than my 9mm. Of course, the focal reducer will change everything.



#8 Napp

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Posted 22 September 2020 - 12:29 PM

4mm is too much for your scope.  Magnification equals the focal length of the scope divided by the focal length of the eyepiece.  2032mm divided by 4mm equals 508X.  508X is way too much power for your scope.  Theoretical maximum usable magnification for a scope is 203mm times 2 equals 406X.  However, the earth's atmosphere generally limits usable magnification for any scope regardless of size to 200X to 250X.  Often it's much less.  There are rare night when you can really push magnification but they are extremely rare - maybe once or twice a year - and you have to be out those rare nights to catch them.  The point is that you would never be able to use a 4mm eyepiece in your scope.  An 8mm eyepiece would produce 250X in your scope.  You will use a longer focal length much more.  I wouldn't recommend a shorter focal length. A zoom is a possibility.  The Baader Hyperion Mark IV 8-24mm is a good quality eyepiece.  I bought one before building my collection of fixed focal length eyepieces.  I still use it to determine what focal length is the best to use or when traveling light.  I also used it for outreach before the pandemic. 


Edited by Napp, 22 September 2020 - 12:32 PM.


#9 willwill

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Posted 22 September 2020 - 01:45 PM

4mm is too much for your scope.  Magnification equals the focal length of the scope divided by the focal length of the eyepiece.  2032mm divided by 4mm equals 508X.  508X is way too much power for your scope.  Theoretical maximum usable magnification for a scope is 203mm times 2 equals 406X.  However, the earth's atmosphere generally limits usable magnification for any scope regardless of size to 200X to 250X.  Often it's much less.  There are rare night when you can really push magnification but they are extremely rare - maybe once or twice a year - and you have to be out those rare nights to catch them.  The point is that you would never be able to use a 4mm eyepiece in your scope.  An 8mm eyepiece would produce 250X in your scope.  You will use a longer focal length much more.  I wouldn't recommend a shorter focal length. A zoom is a possibility.  The Baader Hyperion Mark IV 8-24mm is a good quality eyepiece.  I bought one before building my collection of fixed focal length eyepieces.  I still use it to determine what focal length is the best to use or when traveling light.  I also used it for outreach before the pandemic. 

Thanks, yeah i canceled the 4. Now i see with starsense they want you to use a 10-15MM for one of the alignments, i swear starsense accessory seems as difficult as without it. But, we'll see i guess. I may just wait till i get a few more eyepieces. 



#10 kathyastro

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Posted 22 September 2020 - 02:16 PM

they just look like circles that are kinda blurry unless i zoom way out,

You are aware, I hope, that the knob on the back of the scope is a focus knob, not a zoom control?  Unless you have a zoom eyepiece, the telescope has no zoom capability.  You turn that knob until the circles are as small as you can get them.  That is in focus.


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#11 willwill

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Posted 22 September 2020 - 08:43 PM

You are aware, I hope, that the knob on the back of the scope is a focus knob, not a zoom control?  Unless you have a zoom eyepiece, the telescope has no zoom capability.  You turn that knob until the circles are as small as you can get them.  That is in focus.

I want to say yes i do know, but in reality now that you say that.. When i am turning it, i am thinking in my head how i am getting closer. lol  Tonight, i will give it a go with a clearer mind. I did think it was focusing, but i was also thinking it was focusing as well as coming closer. So what i think you're saying, what you see immediately is what you get and adjusting the focuser will only make that sized object clearer or less clear, and now that i think of it in that sense, i think i definitely need a lower MM than 25, because 25 the planets looked like small balls i couldn't make anything out of.  

 

Thank you for this, while i laughed at your response at first, the more logically i thought about it, i better understand.. I think i thought of it as a focuser, but i was using it like a zoom. heh make sense?


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#12 PPPPPP42

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Posted 22 September 2020 - 11:00 PM

I second the 8-24 zoom eyepiece suggestion, its what I started with and I only replaced it when I went to 2" eyepieces.

The Celestron version is a decent quality cheap option (what I had first) the baader is better and also a little wider angle of view which is nice because zoom eyepieces have a pretty narrow view.

You will likely never need more than 8mm unless you have a night of truly amazing seeing (air stability).

 

Typical crap seeing or the planets being too low in the sky so you have to look through too much air can make the planets look like white or oddly colored fuzzy balls even when you are perfectly focused.

Its obvious when you are at best focus because the target will be its smallest and sharpest and get bigger and fuzzier turning it in either direction.  With crappy seeing its sometimes hard to tell where perfect focus is.  Sometimes the surrounding stars or (or Jupiter's moons) are easier to see perfect focus on.

The only alignment that ever worked for me with the hand controller was 2 star manual using 2 stars that were about 90 degrees apart, and you have to be fairly quick about going between them or it gets messed up.

Its good you have a 12v battery pack, even with the 6SE I had using the built in AA batteries made the tracking go berserk.

I definitely used my F6.3 reducer corrector on all DSO's, not planets or the moon or individual or double stars though.


Edited by PPPPPP42, 22 September 2020 - 11:04 PM.

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#13 wolf454

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Posted 23 September 2020 - 07:05 AM

I recently bought the same scope as you. It included a 25mm ep. With everything being out of stock everywhere, it took me some time to get some other parts to complement this fine scope.

I picked up a nice set of Meade 4000 52 degree 6.7-40mm eyepieces in the classified section for a very reasonable cost. You might want to check it before ordering elsewhere. Also purchased a 7mm Celestron X-cel ep, it is a wider field and longer eye relief eyepiece.

Even though I'm a novice, I have a few suggestions, you might want to add to your toolbox:

1. Purchase either a 12v battery power pack or ac adapter for the scope. I used up a set of AA alkalines the first night. If you're gonna use it remotely, go for the power pack. Celestron brand and many others are available.

2. If skeeters are a nuisance (I live in Georgia so I know too) buy a Patio style thermacell. Available on Amazon, they work great. Keep the cats away from it though.

3. Use the included eyepiece to set up and align your finder before dark on a far away terrestrial object. Be sure to level the tripod and base.

4. You have to set up the alignment if you want it to track. I use 3 point alignment method with the included ep. I tried it with a higher power and lower power ep and results were not as good. I used polaris, Vega, and Jupiter with good results. Whatever brightest stars you can see visually should work. You do not need to identify them, but be sure to slew around when doing it, don't use stars in same vicinity of each other.

5. That's basically it. I don't have the 2 inch diagonal but I've heard it won't clear the base with an eyepiece, be careful when moving the scope to overhead stars (zenith).

I finally received some eyepieces earlier this week, seeing was not the best Monday night when I tried them out. The best I could get to viewing mars and saturn was the 12.4mm eyepiece without distortion. The 6.7 and 7mm were very blurry due to the atmosphere. 12.4mm was impressive, but you should be able to see Saturn's ring and Jupiter clouds with the included 25mm ep. Just experiment a bit you'll figure out which eyepieces to use when, and read others posts here like I've been doing.

Clear skies and enjoy your scope.

#14 willwill

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Posted 23 September 2020 - 11:42 AM

Well, i took it out last night, viewing was quite bad, barely any stars viewable, so it was not a good night for seeing.   Mars was viewable, i messed with the focus and i definitely could see getting it focused, it was just too small to see anything, so definitely a better eyepiece may help. If the sky is better tonight, i will have a 10MM in hand to  see how that works, and then some others coming the next 2-3 days. Starsense was not as bad as i've read it to be, and actually was more in line than i thought,except i could only find planets to align it with, but it did recognize mars on identify when i had it on it. So it must be somewhat aligned. lol



#15 wolf454

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Posted 23 September 2020 - 12:10 PM

I missed the point you already had the starsense unit. That sounds pretty nifty. If you have that you can disregard alignment I suppose ;) I would still assume you will need to check the mount for levelness and let it align each time you set it up. Btw DSO's are spectacular with our scopes too, if you get tired of viewable planets.
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#16 PPPPPP42

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Posted 23 September 2020 - 04:59 PM

You can have bright stars on a clear night with truly crappy seeing so just the visibility of stuff is misleading.  If the stars are twinkling all pretty like, usually the upper air currents are positively boiling and seeing is crap.  If the moon is up sometimes it looks like its underwater when you really zoom in on it because of the way the air currents ripple and wave.

 

One big discomfort in the rectal orifice with the 8SE is that it can take a pretty significant amount of time for it to reach ambient temperature, and even with a steady sky the image can look like its over a boiling pot of water due to the convection currents from the warmer parts.  Making sure that big mirror is fully cooled down is really important.

 

It IS actually worth all the irritation it when the sky and the scope all cooperate at the same time.  Figuring out equipment cool down times and getting everything working efficiently and ready in advance at least gets your end of the bargain in order.



#17 willwill

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Posted 24 September 2020 - 12:41 AM

You can have bright stars on a clear night with truly crappy seeing so just the visibility of stuff is misleading.  If the stars are twinkling all pretty like, usually the upper air currents are positively boiling and seeing is crap.  If the moon is up sometimes it looks like its underwater when you really zoom in on it because of the way the air currents ripple and wave.

 

One big discomfort in the rectal orifice with the 8SE is that it can take a pretty significant amount of time for it to reach ambient temperature, and even with a steady sky the image can look like its over a boiling pot of water due to the convection currents from the warmer parts.  Making sure that big mirror is fully cooled down is really important.

 

It IS actually worth all the irritation it when the sky and the scope all cooperate at the same time.  Figuring out equipment cool down times and getting everything working efficiently and ready in advance at least gets your end of the bargain in order.

Very interesting, i didn't get out tonight, It was pretty cloudy and yeah saw some stars dancing like crazy, i think vega. With the naked eye i can only see a handful around here. With all the trees along the lake we live on, it would block most of the sky in all directions. I may take it back out there this weekend and see what i can pull up. If i get my dock repaired and get some railings on it, maybe down at the end of the dock would be cool. Knowing me, it would be a wet disaster lol ., Hopefully it'll be better out tomorrow night.All i saw tonight was vega and mars. I did see the moon partly around sunset, it seems like the moon has been gone for weeks



#18 PPPPPP42

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Posted 24 September 2020 - 08:10 PM

Florida is so incredibly different from up here in WI that I can't give you any real advice on what sorts of weather systems usually have good viewing before or after but you could probably find some local advice somewhere on here.  There are factors to consider that would tell you what the seeing is probably like even before going outside.

There are even sites that predict if for you: http://www.cleardarksky.com/csk/

 

Up here I tend to get clues about seeing from watching the jet stream maps because some of the fastest most turbulent air seems to like to dance around over WI so bad seeing is common and one day we might have warm air pushed up from the southern US and the next cold air shoved down from Canada.  Generally there are seasons that are commonly better than others here.

Down there I'm not even sure what direction weather usually comes from (SE I think?) and I suppose its very different depending on where in FL you are.

Lots of stuff on here that might be useful including the jet stream map (maybe not so relevant to you) https://www.wunderground.com/

 

You definitely have the latitude advantage down there, the planets will always be much higher in the sky making them much clearer for you.


Edited by PPPPPP42, 24 September 2020 - 08:11 PM.

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