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

Smallest lightest travelli Eaa Scope?

  • Please log in to reply
37 replies to this topic

#1 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 06 April 2019 - 10:44 AM

Hi All,

 

I'm totally new to Eaa, and from advice gleaned on this forum I've been recommended a lodestar 2x with the new Sony ICX829 sensor for use from my suburban light polluted viewing site. I'm thinking along the lines of fast stacking  20 second subs to get a live view experience.

 

https://www.widescre...autoguider.html

 

I was thinking of mounting a very light scope on a mini Skywatcher Az5 gti which has a max capacity of 5kg. Mount weighs 1.3kg. Hoping to get a total grab & go weight of about 5kg or less, so that would leave about 3.5kg for the scope.

 

https://www.firstlig...unt-tripod.html

 

This set up will be used to view DSO's in light polluted skies, not for any visual work.

 

Any suggestions of suitable travel scopes that will do the job?

 

 


Edited by Peter_-_, 06 April 2019 - 10:49 AM.


#2 Hesiod

Hesiod

    Mercury-Atlas

  • *****
  • Posts: 2895
  • Joined: 13 Jan 2013

Posted 06 April 2019 - 11:00 AM

Given the small sensor and large pixel of the Lodestar you may pick a very short focal small refractor if want a somewhat larger fov (I'd guess 300mm or less to have roughly 1° fov).

Depending on the budget may look into something like the Vixen fl55, the small Borgs, or the upcoming William Optic RedCat.

Or go cheap and get a ST80, or even a 50mm finderscope (those are <200mm).

 

Another cheap option, but with a very different outcome, is something like the Vixen VMC95 or 110: these have a 1050mm focal lenght, so expect a very small fov (probably 1/3 of a degree), and slow focal ratios (obviously the 110 is a tad better), forcing to rise the gain and take more/longer exposures.



#3 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 06 April 2019 - 12:19 PM

Given the small sensor and large pixel of the Lodestar you may pick a very short focal small refractor if want a somewhat larger fov (I'd guess 300mm or less to have roughly 1° fov).

Depending on the budget may look into something like the Vixen fl55, the small Borgs, or the upcoming William Optic RedCat.

Or go cheap and get a ST80, or even a 50mm finderscope (those are <200mm).

 

Another cheap option, but with a very different outcome, is something like the Vixen VMC95 or 110: these have a 1050mm focal lenght, so expect a very small fov (probably 1/3 of a degree), and slow focal ratios (obviously the 110 is a tad better), forcing to rise the gain and take more/longer exposures.

 

Hi Hesiod,

 

I've seen some photo's taken with 100mm refractors @20s subs and they seem to show quite good detail in a 20-30 frame stack. Would reducing the aperture down to 80mm, or even a 50mm finder , increase the length of of the exposures by much and make the size of the image scale appear very small?

 

I'd like to try out a cheap set up to begin with to get some idea of the different variables that might effect final images.

 

I can find no reference to what sort of computing power is necessary to run the software: is Ram important, or is the data written directly onto the hard drive? 



#4 davidparks

davidparks

    Viking 1

  • *****
  • Posts: 508
  • Joined: 20 Jul 2017
  • Loc: Battle Creek, MI - USA

Posted 06 April 2019 - 12:54 PM

There is a lot of information over in the Mount Forum on the Skywatcher AZ-GTi.  Here is the longest running thread.

 

And here is what’s possible:  Great for EAA and long exposure AP.

Of course, you can go much simpler, keeping it in Alt-Az, no guiding, no autofocus, etc.  This is just to show you what’s possible with that particular mount.  Many folks use an 80mm refractor, up to a 127 Mak, and C5 SCT.

 

Diagram 1
Diagram 2

Edited by davidparks, 06 April 2019 - 12:58 PM.

  • geminijk likes this

#5 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 06 April 2019 - 01:52 PM

There is a lot of information over in the Mount Forum on the Skywatcher AZ-GTi.  Here is the longest running thread.

 

And here is what’s possible:  Great for EAA and long exposure AP.

Of course, you can go much simpler, keeping it in Alt-Az, no guiding, no autofocus, etc.  This is just to show you what’s possible with that particular mount.  Many folks use an 80mm refractor, up to a 127 Mak, and C5 SCT.

 

 

Hi David,

 

Thanks for your detailed response...Wow! you've put my head in a spin.lol. I'm amazed you can fit so much on such a small mount, very impressive looking set up, and I'd guess quite a lot of money invested.

 

I think I might be better off starting with a clean sheet of paper and ask what you would recommend for a simple but efficient set up with about €1000-1250 euros might look like. 

 

Is €500 for a mono camera adequate or do I need to spend more?

 

Az gti mount looks good?

 

I'm happy to start with cheap st80mm, and update later to better.

 

What would be the minimum computer specs that will run the software?



#6 Hesiod

Hesiod

    Mercury-Atlas

  • *****
  • Posts: 2895
  • Joined: 13 Jan 2013

Posted 06 April 2019 - 01:52 PM

Hi Hesiod,

 

I've seen some photo's taken with 100mm refractors @20s subs and they seem to show quite good detail in a 20-30 frame stack. Would reducing the aperture down to 80mm, or even a 50mm finder , increase the length of of the exposures by much and make the size of the image scale appear very small?

 

I'd like to try out a cheap set up to begin with to get some idea of the different variables that might effect final images.

 

I can find no reference to what sort of computing power is necessary to run the software: is Ram important, or is the data written directly onto the hard drive? 

No, the large-scale details shown in most EAA screenshots are far below the reoslving power of even small telescopes; the lenght of exposure depends on the camera's specs and telescope's focal ratio, while the image scale depends on the sampling (id est, how much of "sky" is seen by each pixel).

Being sampling a function of focal lenght and pixel size according to the formula (mm pixel size/ mm focal lenght)x206265, and the field of view the product of sampling and pixel number (width, height or diagonal), you may check easily if a setup is suited to your aims.

 

Softwares like Firecapture (the one I use for planetary AP, and the same tried when made my mind about EAA) works on very lowly PC (I used a really  low-end 12" laptop with a 2.16GHz N2840 celeron and 2GB ram ), both for the capture and for the live-stacking.

 

I eventually drop my interest in EAA (despite the fact that could have upgraded my mount to use its HC as screen and to control a videocamera, without rsorting to the laptop), so others could give you better advices, but still find a bit awkward the choice of the LodestarX2: it is for sure one of the best pick for guiding, but it is also a rather specialized device and the mix of huge pixels and small sensor would force a very peculiar behaviour upon your setup



#7 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 06 April 2019 - 02:00 PM

No, the large-scale details shown in most EAA screenshots are far below the reoslving power of even small telescopes; the lenght of exposure depends on the camera's specs and telescope's focal ratio, while the image scale depends on the sampling (id est, how much of "sky" is seen by each pixel).

Being sampling a function of focal lenght and pixel size according to the formula (mm pixel size/ mm focal lenght)x206265, and the field of view the product of sampling and pixel number (width, height or diagonal), you may check easily if a setup is suited to your aims.

 

Softwares like Firecapture (the one I use for planetary AP, and the same tried when made my mind about EAA) works on very lowly PC (I used a really  low-end 12" laptop with a 2.16GHz N2840 celeron and 2GB ram ), both for the capture and for the live-stacking.

 

I eventually drop my interest in EAA (despite the fact that could have upgraded my mount to use its HC as screen and to control a videocamera, without rsorting to the laptop), so others could give you better advices, but still find a bit awkward the choice of the LodestarX2: it is for sure one of the best pick for guiding, but it is also a rather specialized device and the mix of huge pixels and small sensor would force a very peculiar behaviour upon your setup

 

Thanks for all that info: it's a complex and confusing subject for a beginner to grasp, especially if they are not very computer savvy. Getting the camera, the scope and the mount and software all working together without making a gross error looks like a bit of a challenge.



#8 Hesiod

Hesiod

    Mercury-Atlas

  • *****
  • Posts: 2895
  • Joined: 13 Jan 2013

Posted 06 April 2019 - 02:12 PM

gallery_215679_8115_59501.jpg

 

To give you an idea, this is more or less the largest field of view I could frame with the asi120 and a 55/300 refractor



#9 barbarosa

barbarosa

    Vanguard

  • -----
  • Posts: 2112
  • Joined: 11 Apr 2010
  • Loc: 130miles W of Yosemite

Posted 06 April 2019 - 07:22 PM

If you are still considering your options over the next few days and if the forecast of clear sky next Tuesday is correct, and if you would find it helpful I will try for some images using a 50mm former RACI finder and now a 50mm straight through guider. The cam is a ZWO 290 mono. Time and clouds allowing I will swap it out with a ZWO 224 color. I will stack using SharpCap.

 

Let me know by PM next Monday or Tuesday by about 7 PM PDT and I will do my best. 

 

You can get buy with a very modest PC for capturing DSO images with a small format sensor. I am using a cheap ACER (Amazon build) 8GB of memory and never taxed, even running a camera and a browser or two and Stellarium. The intel CPU hits gets a workout but I think that is mostly due to Stellarium.



#10 barbarosa

barbarosa

    Vanguard

  • -----
  • Posts: 2112
  • Joined: 11 Apr 2010
  • Loc: 130miles W of Yosemite

Posted 07 April 2019 - 01:13 AM

Saw stars fired up the gear. Not exactly clear but this image will give you an idea of what  you can do with a 50mm finder/guider and a 290 camera. A mono cam so more sensitive than a color cam.

 

Consider the image scale more than the image quality. Oh yes I did not adjust the focus, so its a bit soft.

15s exposures, 27 frames, 405s

Stack_27frames_405s.jpg



#11 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 07 April 2019 - 03:32 AM

Saw stars fired up the gear. Not exactly clear but this image will give you an idea of what  you can do with a 50mm finder/guider and a 290 camera. A mono cam so more sensitive than a color cam.

 

Consider the image scale more than the image quality. Oh yes I did not adjust the focus, so its a bit soft.

15s exposures, 27 frames, 405s

attachicon.gif Stack_27frames_405s.jpg

 

Thank you very much David, that is precisely what I'm looking for. A reasonably cheap and sensitive mono camera which will work well with a small  aperture travel scope to use in LP suburban skies. ☺

 

Yes!

 

I would be absolutely delighted with the resolution and contrast in your image, so a 50mm finder sight will probably suit me very well indeed. 

 

I would be very interested to see the results from the colour 224 camera: how much less sensitivity does it have , my first thoughts are to go for the mono to cut through the  glow and bad transparency and concentrate on getting a result from capturing DSO's that actually appears on the image.


Edited by Peter_-_, 07 April 2019 - 03:34 AM.


#12 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 07 April 2019 - 04:31 AM

A Zwo290 with the Wi-Fi module to connect with Android/iOS tablet or smart phone looks like its the way to go as i haven't had a laptop or pc for the last 5 years.

 

https://www.astrosho...omputer/p,59741


Edited by Peter_-_, 07 April 2019 - 04:32 AM.


#13 nicknacknock

nicknacknock

    A man of many qualities, even if they are mostly bad ones

  • *****
  • Administrators
  • Posts: 11974
  • Joined: 20 Feb 2012
  • Loc: Nicosia, Cyprus

Posted 07 April 2019 - 04:46 AM

There are different size finderscopes which are natively very fast - all the way up to say 80mm. The AZGTi is ok with for example a 80mm triplet refractor with a “proper” focuser and more OTA weight, so a 80mm finderscope will weight much less - around 1,500 grams or so. Other options: Baader Vario finder 60mm, Borg 55FL, Vixen 55FL, Skywatcher 72ED etc.



#14 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 07 April 2019 - 05:07 AM

Looks promising for a PC illiterate like me....lol.

 

Hmmmm...Tablet ☺

 

 

bzbfiOO.jpg


Edited by Peter_-_, 07 April 2019 - 05:09 AM.


#15 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 07 April 2019 - 05:27 AM

There are different size finderscopes which are natively very fast - all the way up to say 80mm. The AZGTi is ok with for example a 80mm triplet refractor with a “proper” focuser and more OTA weight, so a 80mm finderscope will weight much less - around 1,500 grams or so. Other options: Baader Vario finder 60mm, Borg 55FL, Vixen 55FL, Skywatcher 72ED etc.

 

Thank you very much for your suggestions. Coming from binos I'm amazed by the variety of finder scopes available, I never for a moment dreamed you could get ED glass and other sophisticated set ups: they appear to be mini refractors in their own right with tons of accesories to configure them to a multitude of different tasks.

 

A clearer picture is beginning to emerge of what a suitable set up might look like. 



#16 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 07 April 2019 - 12:31 PM

Interesting review of the ASIair Wi-Fi. 
 

https://youtu.be/TwDoKpvajoo



#17 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 09 April 2019 - 08:55 AM

I have used the Az GTi with my small APOs for imaging (in EQ mode) and with a C5 & 3.3 reducer for EAA. Works quite well. Both are very lightweight setups.



#18 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 09 April 2019 - 09:22 AM

I have used the Az GTi with my small APOs for imaging (in EQ mode) and with a C5 & 3.3 reducer for EAA. Works quite well. Both are very lightweight setups.

 

I was looking at the C6 and thought it would be a little bit too heavy for a travel scope. I did glance at the C5 but I never realised you could use reducers with it to get a faster FR than F10. I notice that's it weighs only 2.7kg, that's nearly 2kg less than the C6, which would work out very well as a grab and go. I presume it uses standard 1.25" ep's ?

 

With a 3.3 reducer does that give you a FR of just 3.0? 

 

127mm aperture sounds very attractive Vs. a little 60mm guide scope. ☺


Edited by Peter_-_, 09 April 2019 - 09:23 AM.


#19 barbarosa

barbarosa

    Vanguard

  • -----
  • Posts: 2112
  • Joined: 11 Apr 2010
  • Loc: 130miles W of Yosemite

Posted 10 April 2019 - 02:31 PM

I was looking at the C6 and thought it would be a little bit too heavy for a travel scope. I did glance at the C5 but I never realised you could use reducers with it to get a faster FR than F10. I notice that's it weighs only 2.7kg, that's nearly 2kg less than the C6, which would work out very well as a grab and go. I presume it uses standard 1.25" ep's ?

 

With a 3.3 reducer does that give you a FR of just 3.0? 

 

127mm aperture sounds very attractive Vs. a little 60mm guide scope. ☺

The C-5 is a very good small SCT. Mine is a US made white tube spotter, and it does very well even with very short focal lenght EPs (seeing permitting) and  by all reports the quality of the Chinese made version is consistently good.

 

The C-5 has a 1.25" VB as standard. The spotter version has 45 degree diagonal that you should replace with a 90 degree diagonal. The 45 is not designed for astro work.

 

The C-5 has a disadvantage  that some buyers find compelling, the small price difference from the 6"  . The  spotter version of the 5"  is also relatively expensive, compared with the 6".

 

The work around for price is to buy  a used C-5

 

The f/3.3 reducer usually mentioned is the one formerly made by Meade.  It and the more common f/6.3 reducers are reducers specifically designed to bring  f/10 SCTs to those focal ratios. They could be called 0.33x and 0.63x reducers which is the general style for describing a reducer.  f/10 x 0.33 = f/3.3.

 

There are other reducer options such as,

  • Combining or stackig 2 reducers, e.g., an f/6.3 and a 0.5x. The trick is is to vary the spacing between the two and from the second one to the sensor to find  a more or less undistored image range. Less than f/6.3 but likely more than f/3.3
  • A reducer  or reducer set from Mallincam. 

A small SCT is a good choice and I am happy to be released from my offer to provide an image fro a 224 camera on a 50mm scope. Turns out that I would have to dismount the scope and remove an extension ring held by tiny black grub screws that are invisible when dropped. 


  • DevilJack likes this

#20 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 10 April 2019 - 05:18 PM

The C-5 is a very good small SCT. Mine is a US made white tube spotter, and it does very well even with very short focal lenght EPs (seeing permitting) and  by all reports the quality of the Chinese made version is consistently good.

 

The C-5 has a 1.25" VB as standard. The spotter version has 45 degree diagonal that you should replace with a 90 degree diagonal. The 45 is not designed for astro work.

 

The C-5 has a disadvantage  that some buyers find compelling, the small price difference from the 6"  . The  spotter version of the 5"  is also relatively expensive, compared with the 6".

 

The work around for price is to buy  a used C-5

 

The f/3.3 reducer usually mentioned is the one formerly made by Meade.  It and the more common f/6.3 reducers are reducers specifically designed to bring  f/10 SCTs to those focal ratios. They could be called 0.33x and 0.63x reducers which is the general style for describing a reducer.  f/10 x 0.33 = f/3.3.

 

There are other reducer options such as,

  • Combining or stackig 2 reducers, e.g., an f/6.3 and a 0.5x. The trick is is to vary the spacing between the two and from the second one to the sensor to find  a more or less undistored image range. Less than f/6.3 but likely more than f/3.3
  • A reducer  or reducer set from Mallincam. 

A small SCT is a good choice and I am happy to be released from my offer to provide an image fro a 224 camera on a 50mm scope. Turns out that I would have to dismount the scope and remove an extension ring held by tiny black grub screws that are invisible when dropped. 

 

Aha, those numbers for the reducer make sense. I can see that there is a confusing conflict between visual, AP and EAA that did not appreciate before: Aperture is king for visual, the enemy in AP and quite desirable in EAA with its faster exposure times. Lol.

 

I'm not remotely interested in AP and it's Photoshopped false colour images and long exposure times, but I think Eaa is a very appealing idea with simple tracking  lightweight mounts and standard aperture viewing scopes. Along with binos i think It could work well as a virtually direct observation experience.

 

I will buy the ZWO290 mono and the Wi-Fi hub and a small 50 or 60mm finder scope to get experience , then hopefully if that is a success update to the C5 which will be light enough to sit on the Gti mount.

 

Thanks for all the really useful advice that has helped me make the correct choices. ☺



#21 Astrojedi

Astrojedi

    Soyuz

  • *****
  • Posts: 3790
  • Joined: 27 May 2015
  • Loc: SoCal

Posted 10 April 2019 - 06:19 PM

Best of luck. David gave a very thorough answer to your questions. I would add that I find the C5 to be an excellent travel scope for visual deep sky observing as well as EAA (with a Meade 3.3 reducer). The C6 really pushes the Az-GTi and I would not recommend it for EAA.



#22 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 11 April 2019 - 04:51 AM



Best of luck. David gave a very thorough answer to your questions. I would add that I find the C5 to be an excellent travel scope for visual deep sky observing as well as EAA (with a Meade 3.3 reducer). The C6 really pushes the Az-GTi and I would not recommend it for EAA.

 

The Nextstar C5 & C6 seem to sit on the same heavy go-to mount .

 

tRkYWsk.jpg

 

Just the C5 scope and Nextstar mount without tripod weigh in at 17.6lbs (8kg) which would make it too heavy for hand baggage, so it's makes sense that the C6 is too heavy for the little AZ gti mount which only weighs 6lbs/ 2.7kg on it's own.

 

Really love those beautiful images you took of the M87 black hole, it's extraordinary to think that an amateur can actually see that far into deep space with a simple low cost astro camera and a standard visual C8 scope. ☺



#23 Peter_-_

Peter_-_

    Vostok 1

  • *****
  • topic starter
  • Posts: 165
  • Joined: 05 Feb 2019

Posted 12 April 2019 - 08:22 AM

This seems to be the biggest aperture lightweight finder scope I can locate which is 70mm and weighs only 1.2lbs/0.5kg, the same as the 50mm and 60mm sizes.

 

Anyone got one?

 

Orion 70mm multi-use finderscope: €105

https://www.teleskop...ts_id=7488#desc

 

 

lmKelZq.jpg



#24 barbarosa

barbarosa

    Vanguard

  • -----
  • Posts: 2112
  • Joined: 11 Apr 2010
  • Loc: 130miles W of Yosemite

Posted 12 April 2019 - 02:22 PM

 

The Nextstar C5 & C6 seem to sit on the same heavy go-to mount .

 

 

Just the C5 scope and Nextstar mount without tripod weigh in at 17.6lbs (8kg) which would make it too heavy for hand baggage, so it's makes sense that the C6 is too heavy for the little AZ gti mount which only weighs 6lbs/ 2.7kg on it's own.

 

AFAIK the mount for the 4/5 SE is smaller, lighter and has a different drive train than the 6/8 mount. Celestron gives the weights for the 5" OTA as 2.7kg and the mount as 3.2kg for a total of 5.9kg. The 4/5 mount also has a built in wedge. Some say it works, some say it works with a simple modification and some say it doesn't work. I had this mount but never tried the wedge, I am agnostic.

 

Clearly weight followed by physical dimensions are the critical criteria, and you seem to prefer something like a finder/guider (fast and short) to which you can attach a camera. The Orion 70mm will work but you should read the manual's discussion about diagonals or adapters to reach focus.

 

Orion is the brand name of a retailer based in California. They are not a manufacturer and quite often Orion products are also available under different brand names. Alternatively you might consider a  70mm with a straight rather than a tapered tube to get a stiffer mounting system and allow you to move the scope off the factory mounting stalk. But of course the price goes up.

 

Anyway good luck to you.



#25 Alien Observatory

Alien Observatory

    Viking 1

  • *****
  • Posts: 822
  • Joined: 13 Nov 2015

Posted 13 April 2019 - 02:35 PM

My Travel and Portable mount is a Sky Watcher All View Mount (it can be powered with AA batteries).  I use it with a variety of DSLR Lenses, 50 mm and 60 mm Refractor Telescopes and for a camera, I use my Nikon D3400 (battery powered)  and other ZWO cams.  Also have an ASI Air to use the iPad with the ZWO cams....just an alternative path for portability / travel...Pat Utah smile.gif

Attached Thumbnails

  • IMG_0285.jpg
  • IMG_1199.jpg

Edited by Alien Observatory, 13 April 2019 - 09:03 PM.



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