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What can I see with a 70mm telescope?

beginner Celestron planet refractor
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#26 IsaacSucks2

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Posted 28 May 2020 - 05:36 PM

And, also can see detail on mars? I know aeajr already answered my question but I wanted to see if you guys had the same answer.

#27 aeajr

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Posted 28 May 2020 - 05:51 PM

This is Mars using an 8"/203 mm telescope. It gathers about 8.4 times as much light as a 70 mm

https://www.youtube....h?v=m8UmGvy8CN8

 

Others can comment on this as a reference point. 



#28 astrohamp

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Posted 28 May 2020 - 06:05 PM

Good for you IsaacSucks2 and enjoy the views.  My first view of Saturn was through a 70mm shorter focal length scope and at the time amazing.

You could use a Field of View calculator here entering your telescope focal length, aperture, and eyepiece information.  The local object catalog is limited to the Messier and solar system objects although one can 'search' for many more.   This will allow you to view the object through a virtual and similar telescope to see if the object has potential for viewing, scale wise.  Many will be dim if not invisible until you develop your observing skills like averted vision.
 



#29 SteveG

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Posted 28 May 2020 - 06:28 PM

And, also can see detail on mars? I know aeajr already answered my question but I wanted to see if you guys had the same answer.

Probably not much, but possibly on an exceptional night of seeing. Mars handles very high power well.


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#30 SteveG

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Posted 28 May 2020 - 06:39 PM

I think I’ve got the hang of the EQ mount. I will consider not buying the accessory kit, I got very nice views of every planet last night. It’s a very neat scope, I think I will keep this one for a while until I can buy a better one. The only reason I wanted the kit was because it came with a Barlow, a 15mm, and that moon filter. But I realize I could probably buy some better quality ones for a higher price. Is there anyway to post images on here? And also what other eyepieces should I buy? 15mm?, 8mm?, 32mm?

I think you would benefit with these low-cost wide-field eyepieces. They will work well with your scope, and give you a nice variety of magnification. They are the same as the Orion Expanse, 66 deg afov:

 

https://www.amazon.c...tronics&sr=1-37



#31 oshimitsu

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Posted 28 May 2020 - 06:47 PM

If I were you I'd keep the classifieds open when you're on your PC. I've picked up multiple items at a huge discount using the classifieds. Since most of us in this hobby are very picky with our optics they are generally in pristine condition.



#32 Sketcher

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Posted 28 May 2020 - 07:33 PM

Some thoughts, experiences, etc. about some of the things that have been discussed in this thread.

 

Eyepiece kits

 

I've been an amateur astronomer for 50+ years.  I have several telescopes and a wide variety of eyepieces including some costing $300+ each.  But I also actually have one of the Celestron eyepiece kits.  Furthermore, just to refresh my memory, I just came inside from checking out each eyepiece -- individually and with the kit 2x Barlow.

 

The bad news:  a) The 6mm and 8mm eyepieces have very short eye-relief, meaning that in order to see more of the field-of-view, you need to get your eye uncomfortably close to the eye-lens of the eyepiece.  b) Some of the eyepieces and eyepiece-Barlow combinations exhibit a small amount of vignetting, meaning that it may not always be possible to see the field-stop at the edge of the field-of-view.  c) Apparent fields-of-view are all in the neighborhood of 52° (Some people prefer wider apparent fields, but for most purposes a 52° field will do just as well from a practical point of view).

 

The good news:  a) All of the eyepieces provide sharp, crisp images throughout most of the visible fields-of-view.  You will not find anything that can provide noticeably sharper images than what is provided by these eyepieces -- regardless of much money you spend.  b) All the eyepieces, including the Barlow, are of high optical quality.  c) Eye-relief is longer with the longer focal-length eyepieces -- being quite comfortable with the 32mm and 17mm eyepieces.  The rubber "eye-cups" can be folded down on these eyepieces to allow one's eye to get closer to the eyelenses.

 

The Celestron kit I have has the following Plossl eyepieces: 32mm, 17mm, 13mm, 8mm and 6mm.  All are usable singly as well as with the included 2x Barlow (depending on how much magnification one's telescope and sky conditions can tolerate).

 

Personally, I greatly prefer using something similar to the Orion Expanse 9mm and 6mm eyepieces for the shorter focal-lengths.  The eye-relief is tremendously more comfortable and the wider apparent fields-of-view are nice to have.  But I have to repeat that going with other (more expensive) eyepieces will gain nothing in terms of image sharpness.  The gains that you pay more for are in terms of comfort in use and wider apparent fields-of-view -- and if one has the added money to spend, those features can be worth paying more for.

 

The filters:  Some people like filters, some don't.  It doesn't hurt to have a few to experiment with.  If nothing else, they can be fun to use to observe various full moons -- a "blue moon", etc.  For serious planetary work, other filters would tend to be better, especially for use with smaller telescopes.  On the other hand, the green filter may be quite practical for Venus.  Quality-wise, these filters are certainly "good enough" to actually use.  Oh, and many people like using a "moon filter" (included in the kit).

 

Equatorial mounts:  Of course, this is a matter of personal preference.  For those who understand the naked-eye sky, how earth's rotation is seen to effect the apparent paths of stars in different parts of the sky; an equatorial can be an intuitively simple and enjoyable mount to use.  For others, an alt-az mount may well be a better choice.  Personally, I have at least four equatorials along with several alt-az mounts.  Sometimes I prefer one, other times i prefer the other.  But most of the time I prefer using equatorials.

 

What can you see with a 70mm telescope?  Here, much depends on the person behind the eyepiece and their sky quality (darkness as well as seeing conditions).  The best way to find out is to get out and look.  Of course, the sun (with a proper, objective solar filter), moon, planets, double-stars, and open clusters will be within reach.  Deep-sky objects will be very dependent on how dark one's sky is.  From a dark sky, a 70mm telescope is capable of showing hundreds of galaxies, nebulae, etc.  But from a severely light-polluted sky few, if any, galaxies and nebulae will be visible.

 

Mars:  This one's all over the place due to a multitude of variables that can effect what one might see or not see.  Fifty yeas ago I saw far more on Mars with a 65mm telescope than what could be made out in the video that aeajr posted a link to.  I actually drew up my own Mars map while using that 65mm telescope.  The video shows how Mars looked with someone's 203mm telescope.  Contrast that view with this one:

 

Mars 6 inch F 6.5 achromatSketcher   text
 
The 6-inch telescope used was poorly suited for observing Mars.  A 70mm telescope would be able to show much of what's visible in the above sketch -- assuming cooperative sky conditions, an experienced observer, a Mars near opposition, etc.
 
In general:  The more one looks, the more one will see.  The bubbly blob (Mars) in the video is what most tend to see when observing the "red planet".-- regardless of the telescope being used.  It takes persistence and repeated observations, night after night in order to see more than that "blob" when observing Mars.  But I insist:  A 70mm telescope is capable of showing interesting details on Mars; but it's better to not expect anything other than a yellow-orange, boiling blob.  The trick is to keep studying that blob.  Eventually seeing conditions will improve and your increased experience will kick-in and you'll start seeing more.

Edited by Sketcher, 28 May 2020 - 07:42 PM.

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#33 oshimitsu

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Posted 28 May 2020 - 09:23 PM

 If the kit you're looking at is the Celestron one I'd pick it up honestly. I bought that kit when I was starting out and if only for the 32mm, 17mm and moon filter it's worth it. The 32mm is my most used eyepiece, might I suggest looking at the Apertura eyepiece kit? It appears to be the exact same set but rebranded and cheaper.

Just to reinforce what Sketcher said; The eye relief on the 32mm and 17mm are wonderful and provide very crisp views. Now I do not care for the shorter focal length eyepieces but that isn't a jib at their quality, I just don't enjoy the 2 or 3mm eye relief. Plossl eyepieces are great general purpose eyepieces and provide bright views because they contain less glass than the wider FOV designs. Some argue that the Plossl is the best choice for planetary viewing but I can't comment on that because all I use are Plossls and I have 2 Nagler designs but I don't use them often and never for Planetary because I don't care for the wide FOV.

I got a bit off topic but anyhow, if you want that eyepiece kit I'd seriously look at the Apertura kit and get it. They are fine Plossls and if you went the other route and bought only 1 32mm Plossl you'd pay 40-50 dollars, and over 100 for a Televue Plossl



#34 JohnnyBGood

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Posted 29 May 2020 - 07:28 AM

 If the kit you're looking at is the Celestron one I'd pick it up honestly.

Yeah, but it's not that kit.The one in question only comes with a 6mm Ploessl, a 15mm Kellner, and a 2x Barlow and only half the filters as the larger all Ploessl kit.



#35 IsaacSucks2

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Posted 29 May 2020 - 02:26 PM

yeah it’s a smaller kit



#36 IsaacSucks2

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Posted 30 May 2020 - 08:15 PM

Thank you for all your help guys. One more question, can I see any star clusters?

#37 aeajr

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Posted 31 May 2020 - 07:22 AM

Thank you for all your help guys. One more question, can I see any star clusters?

Hundreds of star clusters.

Planets

Double stars

Bright nebula

The Moon.

 

I gave you a large list in my earlier post.  The thing you need to learn is how to find them since you can't see them naked eye.

https://www.cloudyni.../#entry10220272

 

 

A great source of appropriate targets are the binocular newsletters, lists and books.

https://binocularsky...2d&e=cd4cb98b06

 

The Astronomical League is also a great source of guidance when learning to observe, especially if you don't have a club nearby.

https://www.astrolea.../observing.html


Edited by aeajr, 31 May 2020 - 07:26 AM.

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#38 JohnnyBGood

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Posted 01 June 2020 - 09:45 AM

Star clusters are my favorite targets since there are a bunch of them that are easy to see despite quite a bit of light pollution. And if you can get out to dark skies, there are several (such as the ones in Cassiopeia) that I think looked cooler in my 76mm scope than in my 130mm and 203mm. Turn Left At Orion gives you a good idea of what each target will look like in a 70mm refractor.



#39 oshimitsu

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Posted 01 June 2020 - 11:01 PM

Thank you for all your help guys. One more question, can I see any star clusters?

Absolutely! You're options for clusters are vast and there are a ton of them right now. I've been spending a bit of time around Antares looking at globular and open clusters, they should be fairly easy to find if you follow along using Stellarium. 



#40 GeorgiBG

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Posted 04 June 2020 - 05:57 PM

Today I finally tried out my 70x700 refractor on Jupiter and Saturn so this is what can you see (and remember that I'm still a newbie):

 

Jupiter is with barely noticeable cloud bands (the full Moon is not helping either but I believe that they can be seen otherwise), Europa, Ganymede, Io and Callisto are seen as small stars. Saturn clearly shows it's beautiful rings, I didn't manage to see Titan though I'm sure it's visible. The moon, on the other hand, looks gorgeous on any magnification and the terminator line is a feast for the eyes to watch. :)

 

I used 70x magnification for Jupiter and Saturn, at 28 they are just seen as glowing disks, on 140x (with a Barlow lens) there is barely any difference and the telescope starts to show some chromatic aberration (on the other zoom levels is fine however).

 

I will try it on some of the DSO's later and report here my findings.



#41 marsobserver137

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Posted 05 June 2020 - 07:36 PM

nice, I also barely saw Jupiter’s cloud bands, The moons are visible though. With Saturn I definitely saw the rings, I may have seen a hint of the Cassini division but not to sure. I may have seen Titan to but not sure. I saw mars and it’s pretty neat, I could see the polar ice cap and barely an albedo feature. A few weeks ago I saw Venus and it was a beautiful crescent. I also saw mercury, it was not so impressive but looked amazing nonetheless. It just looked like a small oval. When it is easier to view I’m going to take a look at uranus and see if I can see anything. The moon is amazing by the way.
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#42 GeorgiBG

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Posted 06 June 2020 - 03:40 AM

nice, I also barely saw Jupiter’s cloud bands, The moons are visible though. With Saturn I definitely saw the rings, I may have seen a hint of the Cassini division but not to sure. I may have seen Titan to but not sure. I saw mars and it’s pretty neat, I could see the polar ice cap and barely an albedo feature. A few weeks ago I saw Venus and it was a beautiful crescent. I also saw mercury, it was not so impressive but looked amazing nonetheless. It just looked like a small oval. When it is easier to view I’m going to take a look at uranus and see if I can see anything. The moon is amazing by the way.

Yes, the Moon manages to amaze me every time when I'm looking at it. Mars is on the horizon too early for me to observe it and no chance for Venus still but they are both easy targets to find and to observe. I'm glad you like the views, the key here is to not have high expectations which will lead to great results after a few observations because you will see more and more every time when you observe.



#43 Tony Flanders

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Posted 06 June 2020 - 04:09 AM

Today I finally tried out my 70x700 refractor on Jupiter and Saturn so this is what can you see (and remember that I'm still a newbie):
 
Jupiter is with barely noticeable cloud bands (the full Moon is not helping either but I believe that they can be seen otherwise), Europa, Ganymede, Io and Callisto are seen as small stars. Saturn clearly shows it's beautiful rings, I didn't manage to see Titan though I'm sure it's visible. The moon, on the other hand, looks gorgeous on any magnification and the terminator line is a feast for the eyes to watch. smile.gif


Actually, Jupiter is much too bright to be affected by moonlight. The biggest problem is that Jupiter is in Sagittarius, the southernmost constellation of the zodiac. Even at its best, it will be very low in the sky for observers north of latitude 40N, which includes almost all of Europe as well as much of North America.

And right now Jupiter doesn't reach its highest until about 4 a.m., which is not a very popular time for observing. It will be better placed in the evening sky in a couple of months.


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#44 GeorgiBG

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Posted 06 June 2020 - 05:47 AM

Actually, Jupiter is much too bright to be affected by moonlight. The biggest problem is that Jupiter is in Sagittarius, the southernmost constellation of the zodiac. Even at its best, it will be very low in the sky for observers north of latitude 40N, which includes almost all of Europe as well as much of North America.

And right now Jupiter doesn't reach its highest until about 4 a.m., which is not a very popular time for observing. It will be better placed in the evening sky in a couple of months.

Your description nails it down. I'm at 43N and indeed I must wait quite a lot before even trying to observe it. For a moment I though that my telescope is guilty about the brightness.

 

EDIT: Tony Flanders, maybe I found a solution to the brightness problem: http://www.astronomi.../aperture-mask/

 

I will test it today and report the results (looks like the best teacher is the experience).


Edited by GeorgiBG, 06 June 2020 - 09:37 AM.


#45 fadheloo

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Posted 06 June 2020 - 01:10 PM

Ill just list what i was able to see other than planets/moon with my 80mm refractor (little to no difference between it and the 70mm) in my bortle 9 sky 

 

The open star clusters M6/M7 

M44 Beehive cluster

M13 Globular cluster

M22 Globular cluster

M31 Andromeda galaxy is pretty easy to see specially with averted vision

i think i was able to spot M4 cluster  also (i spotted it by mistake while looking at antares lol)

 

all that and i'm only 1 month old into this hobby

Haven't tried anything else than other galaxies , which i failed to observe ill say i tried only around 20 of the messier objects 


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