Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Can anyone help me make sense of these and provide some guidance?

  • Please log in to reply
8 replies to this topic

#1 iknowadrian

iknowadrian

    Lift Off

  • -----
  • topic starter
  • Posts: 3
  • Joined: 25 Aug 2019

Posted 25 August 2019 - 03:59 PM

Hey guys - just moved into a new apartment in a cool city. Looking for a scope to browse around the city and look out at the water.

Ideally, something a bit smaller, but still strong enough that I could zoom In and see the painting on the wall of the art gallery ~2000ft away (not literally but a strong zoom is desired) haha

 

I was eyeing the Celestron C70 Mini Mak but also the C90 (and getting a zooming EP).

 

But im new to this so im getting caught up in all the details and its becoming overwhelming. Maybe Im looking at this all wrong and the the larger aperture is going to offer much in performance when it comes to just city viewing? Maybe a cheaper Refractor or spotting scope? Want it to also look nice on display some I'm avoiding binoculars.

 

Any suggestions or guidance would be really helpful! Thank you :)



#2 markb

markb

    Mariner 2

  • *****
  • Posts: 220
  • Joined: 16 Jun 2006
  • Loc: Long Island; in transition to Arizona

Posted 25 August 2019 - 05:06 PM

A well reviewed 70mm-80mm spotter would do nicely, but you need to see if it matches your eyepiece choices.

Short tube refractors might not satisfy the close-up urges or the wallet, but have the greatest utility if you take it outside for astro use. F7 refractors may be too bulky for you to leave out. Visitors will be intrigued.

A C90 would be excellent, I think a 70 minimak may have too many compromises. My photo style barrel focusing f12 etx90 relative is the one I held onto for this purpose, the rotating barrel focus is the easiest type for terrestrial use. Something similar would be ideal. Long discontinued I think, though. Others may also focus that way, including older C90s.

If money is an issue, C90s and C5s can be very affordable used, and you can place a want ad. Etx90 otas are cheap and pretty, but a pain to focus.

Good luck!

Edited by markb, 25 August 2019 - 05:10 PM.

  • iknowadrian likes this

#3 scadvice

scadvice

    Apollo

  • *****
  • Vendors
  • Posts: 1298
  • Joined: 20 Feb 2018
  • Loc: Lodi, California

Posted 25 August 2019 - 05:07 PM

What is the max amount of cash your willing to spend? That makes it easier for us to suggest. 


  • iknowadrian likes this

#4 SeattleScott

SeattleScott

    Fly Me to the Moon

  • *****
  • Posts: 5688
  • Joined: 14 Oct 2011

Posted 25 August 2019 - 05:15 PM

90mm Mak sounds perfect for your purposes.

Scott
  • GalaxyPiper and iknowadrian like this

#5 barbarosa

barbarosa

    Vanguard

  • -----
  • Posts: 2173
  • Joined: 11 Apr 2010
  • Loc: 139 miles W of the Awahnee Hotel

Posted 25 August 2019 - 05:43 PM

A painting on the wall at 2000', well a 90mm Mak could be just the scope.

 

I have an old 90mm Mak w/25mm EP pr a 12 to 24 zoom in the living room as a spotter and it works. I am however just as likely to grab a pair of binoculars, an old 7x35 or a much newer 10x42.My wife always goes for the bins.  The big difference is field of view.  A deer or cow or turkey or person is meat for the 90. A flock of birds, several cattle or dear and the bins are better. Maks have a narrow field of view. I personally would not start with a Mak or an SCT or a long focal length reflector because of the narrow field of view. Of course if you know now that that painting is the essence of your targets a small Mak might do it.


Edited by barbarosa, 25 August 2019 - 05:47 PM.

  • iknowadrian likes this

#6 macdonjh

macdonjh

    Skylab

  • *****
  • Posts: 4203
  • Joined: 06 Mar 2006

Posted 25 August 2019 - 05:43 PM

Aperture helps with light gathering which is useful for star gazing, but not as important for looking at artwork down the street during the day time.  Without getting overly complicated, whichever scope you choose for stargazing will likely be suitable for looking at the art gallery.

 

A Celestron 90mm Maksutov ("C90") or 5" Schmidt Cassegrain ("C5") would be fine for looking at the moon, bright planets (Mars, Jupiter, Saturn) and bright deep sky objects.  

 

Without going into the math (a topic for a different thread, and many already exist), a C90 with a 32mm Plossl eye piece will allow you to see 1.3o of sky and about 45 feet of the gallery's wall at once.  Since the C5 has a similar focal length its field of view will be the same, but the images it show you will be brighter.

 

That 32mm Plossl eye piece will provide almost 40x magnification in either scope.  An eye piece with a focal length of 17mm will provide 75x, 12.5mm 100x, etc.

 

One key accessory you'll want for looking at the art gallery is a "correct image diagonal", also called an erecting prism.  If you purchase a scope with a "star diagonal" you'll still be able to see what you want, but the art gallery will look upside-down.


  • markb and iknowadrian like this

#7 markb

markb

    Mariner 2

  • *****
  • Posts: 220
  • Joined: 16 Jun 2006
  • Loc: Long Island; in transition to Arizona

Posted 25 August 2019 - 06:05 PM

Forgot about the erectors. Avoid the .965 accessories and eyepieces some of these small scopes use. An enlarging ring to SCT threads can simplify buy things like erectors, as can T2 conversion rings available online.

I just converted my photo 90 from 34.6mm to T2 42mmx.75 threads and added a T2 clamp ring visual back for eyepieces etc. Much better than the SCT adapter for me.

As far as 45 degree erectors, the Baader one is affordable, well figured and tough to beat. A astro grade one is available at a higher price, but the regular one os perfect for spotting duties. Many 45 degree erectors are trash.
  • iknowadrian likes this

#8 iknowadrian

iknowadrian

    Lift Off

  • -----
  • topic starter
  • Posts: 3
  • Joined: 25 Aug 2019

Posted 26 August 2019 - 07:09 PM

Thanks for all the replies!!

 

I've learned a lot since the post about focal length, focal ratio (and CA), etc. 

 

So I think I've narrowed it down to three scopes: 

 

1. The C70 Mini Mak has 750mm focal length and magnification of 25x to 75x with the included eye pieces, a focal ratio of f/11 so less CA and is ~$140 CDN

 

2. The Explore FirstLight 90 has a 500mm focal length and 25x or 50x magnification with the included eye piece but has a focal ratio of f/5.5 so more CA and is ~$135 CDN ...However, learned that this one will have a wider field of view (haven't figured out the math on that yet) but basically, I have less magnification when scanning around the city with a wider field of view which would be good. 

2. The Meade Infinity 70az has a 700mm focal length and a 27x to 77x magnification with the included eye piece and f/10 ratio so lesser on the CA side and is ~$114 CDN 

 

I like the included maximum magnification of the C70 and Infinity 70, but attracted to the wide field of view (especially when at lower magnifications) of the FirstLight 90

 

Since they're all around the same price point, I could go either way, maybe add a zooming eye piece for the first two. 

 

But for scanning around the city, and the odd peek up at the moon or Saturn, what do you guys suggest, any of those three? or something else? 



#9 barbarosa

barbarosa

    Vanguard

  • -----
  • Posts: 2173
  • Joined: 11 Apr 2010
  • Loc: 139 miles W of the Awahnee Hotel

Posted 27 August 2019 - 02:18 PM

Give some thought to bigger binoculars on a tripod, anything from the  Celestron 15x70 SkyMaster Binocular  and up and a serviceable tripod ($100 Can) or get a used one from CL or similar. As you will see the range of magnification in this product line goes from 15x to 25x and the field of view is much greater than you can get with a Mak or SCT.

 

I've owned a C-5 for years and it is a great scope for astronomy or spotting, but daytime seeing usually limits the top magnification and the FOV is narrow. You need a finder scope sometimes. Also not the sizeable price gap from a small achromat or Mak. 

 

I have looked through a Mak smaller than 90 mm and it was not inspiring. I would rather have used the 8x50 finder scope that came with my 9.25" SCT.

 

I have an erect image 45 degree prism diagonal and never use it. The flip mirror in the 90 mm and the oem 1.25" prism star diagonal on an SCT both provide an erect image but left-right reversed, something you soon accommodate. An Amici prism will have two drawbacks. The diameter of the light cone will be smaller and in some conditions you can see a vertical line caused by the complex two part prism. Some less expensive Amici diagonals have a very narrow light path which also may be noticeable. That said they often good enough for terrestrial and casual astronomy.

 

The QC on larger low price bins is legendary, and you can find many complaints about collimation, But there are more satisfied owners than the other and who cares if you buy from a dealer with a good return policy?




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics