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ebeyonder
member
Reged: 10/16/09
Posts: 92
Loc: Cambridge, MA, USA; Singapore
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Hi all,
After realising that a WO FLT110-TEC with a ST80 as guidescope might be too heavy for an Orion Sirius Mount, I have decided to go for a 50mm finderscope option.
I already have an Orion Starshoot Autoguider so will be using that as the camera for the guidescope. I would have bought the KWIQ package as an all-in-one deal, but the current price of around USD380 strikes me as too high.
After some research, it seems that a normal 50mm finderscope would require some modification - something which I am keen to avoid if possible because I don't have the correct DIY tools.
I am thus looking at some finderscopes which can accept 1.25" eyepieces and can be focused manually. Stellarvue seems to offer some, notably the SV50, and SV60. I can possibly get them for about USD120 used which, when combined with the Orion guider and rings, etc, would still be less than the cost of the KWIQ.
I have some questions which I would be grateful for any help on:
1. Would a SV50/60 guidescope work with the WO FLT-110 TEC considering the appropriate focal lengths, etc? The WO is 700mm or so, I believe.
2. Can I just put the Orion Starshoot Autoguider into the SV50/60 without any modification to the SV50/60? I have read on other threads that there might be some focusing distance issues with using finderscopes - is this likely to be a problem here?
3. How do I mount the SV50/60 on my FLT? The FLT has two rings with three threaded screw holes on them... I have no experience with refractors and rings (having used ETX gotos before only) so I would be interested to know the proper name of the plate, etc I need... there seems to be so many floating around.
Thank you very much for any comments!
--------------------
Scopes: Meade ETX-90; LX-90 8"; William Optics FLT-110 with TEC optics; Stellarvue SV80S with LOMO optics
Mounts: Orion Atlas EQ-G mount (Hypertuned); iOptron SmartStar-E GOTO AltAz Mount
Imaging gear: Orion StarShoot Pro v. 2 Deep Space Colour CCD; Meade DSI Pro III Monochrome CCD; DMK 21AU04.AS; Meade DSI I; Celestron Neximage
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groz
Pooh-Bah
Reged: 03/14/07
Posts: 1288
Loc: Duncan, BC
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Save yourself a whole lot of grief and fuss. The trick to getting the 9x50 and camera attached, as you have discovered, is finding the right hardware to mate them all, and end up with something that will come to focus correctly. The folks at KW have the correct finder + adapter combination.
If you already have the camera, call em up and order the other parts, sans camera.
For our first one, I ordered the whole package from them, it works great. When we decided to move the second telescope away from the ssag+st80 combo, I bought the 9x50 and adapter hardware from them, to use with the ssag we already had.
No muss, no fuss, everything fits, focusses correctly, and just works. A far simpler solution than trying to jury rig something together.
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ebeyonder
member
Reged: 10/16/09
Posts: 92
Loc: Cambridge, MA, USA; Singapore
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Thanks groz... I may just be heading in that direction. So their finderscope works by combining the SSAG directly with it? No need to focus, etc?
May I also ask what their mount is like. I have the WO rings to put the finderscope on. It has about 3 threaded screw holes. Is it possible for the mount to go there?
Thanks for all your help.
--------------------
Scopes: Meade ETX-90; LX-90 8"; William Optics FLT-110 with TEC optics; Stellarvue SV80S with LOMO optics
Mounts: Orion Atlas EQ-G mount (Hypertuned); iOptron SmartStar-E GOTO AltAz Mount
Imaging gear: Orion StarShoot Pro v. 2 Deep Space Colour CCD; Meade DSI Pro III Monochrome CCD; DMK 21AU04.AS; Meade DSI I; Celestron Neximage
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ebeyonder
member
Reged: 10/16/09
Posts: 92
Loc: Cambridge, MA, USA; Singapore
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I may be able to get a SV50 cheaply... does anyone have any experience with this and an Orion starshoot autoguider? Thanks..
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Scopes: Meade ETX-90; LX-90 8"; William Optics FLT-110 with TEC optics; Stellarvue SV80S with LOMO optics
Mounts: Orion Atlas EQ-G mount (Hypertuned); iOptron SmartStar-E GOTO AltAz Mount
Imaging gear: Orion StarShoot Pro v. 2 Deep Space Colour CCD; Meade DSI Pro III Monochrome CCD; DMK 21AU04.AS; Meade DSI I; Celestron Neximage
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Jared
Carpal Tunnel
Reged: 10/11/05
Posts: 2922
Loc: Piedmont, California, U.S.
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Quote:
Hi all,
After realising that a WO FLT110-TEC with a ST80 as guidescope might be too heavy for an Orion Sirius Mount, I have decided to go for a 50mm finderscope option.
I already have an Orion Starshoot Autoguider so will be using that as the camera for the guidescope. I would have bought the KWIQ package as an all-in-one deal, but the current price of around USD380 strikes me as too high.
After some research, it seems that a normal 50mm finderscope would require some modification - something which I am keen to avoid if possible because I don't have the correct DIY tools.
I am thus looking at some finderscopes which can accept 1.25" eyepieces and can be focused manually. Stellarvue seems to offer some, notably the SV50, and SV60. I can possibly get them for about USD120 used which, when combined with the Orion guider and rings, etc, would still be less than the cost of the KWIQ.
I have some questions which I would be grateful for any help on:
1. Would a SV50/60 guidescope work with the WO FLT-110 TEC considering the appropriate focal lengths, etc? The WO is 700mm or so, I believe.
It should work fine. Anything over about 300mm focal length will be adequate for guiding a 715mm fl scope. The only trick is to have enough focal length so that the FWHM of your guide stars covers two or three pixels not just one, and you can always achieve that by mis-focusing slightly if necessary.
Quote:
2. Can I just put the Orion Starshoot Autoguider into the SV50/60 without any modification to the SV50/60? I have read on other threads that there might be some focusing distance issues with using finderscopes - is this likely to be a problem here?
3. How do I mount the SV50/60 on my FLT? The FLT has two rings with three threaded screw holes on them... I have no experience with refractors and rings (having used ETX gotos before only) so I would be interested to know the proper name of the plate, etc I need... there seems to be so many floating around.
Thank you very much for any comments!
Don't know the answers to your other questions--sorry.
--------------------
- Jared Willson
- A few refractors
- A couple of GEM's
- One camera
- Two eyeballs
- Some heavily light polluted skies
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adamsp123
professor emeritus
Reged: 11/20/08
Posts: 556
Loc: welshpool mid wales UK
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Hi there are some ideas here
http://stargazerslounge.com/diy-astronomer/84726-diy-finder-guider.html
I had some spare bits I could use but "beamish" had a great idea that is cheap and works
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SkyWatcher 120ED PRO, GSO 200mm F4 Astrograph, Meade 10" SNT, WO 72ED & 66ED
Vixen Sphinx and Vixen Atlux with starbook,
QHY5 guider, Modded Canon 1000D, Baader MPCC.
WO Flattener III
Don't you wish there were a knob on the TV to turn up the intelligence? There's one marked 'Brightness,' but it doesn't work."
TV is called a "medium" because it is neither rare nor well done.
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groz
Pooh-Bah
Reged: 03/14/07
Posts: 1288
Loc: Duncan, BC
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Quote:
It should work fine. Anything over about 300mm focal length will be adequate for guiding a 715mm fl scope. The only trick is to have enough focal length so that the FWHM of your guide stars covers two or three pixels not just one, and you can always achieve that by mis-focusing slightly if necessary.
We use the Kwiq here on both of our kits. QHY5/ssag in the 9x50 finder, which has 175mm focal length. The attached shot is a little piece out of a shot from a few months ago taken during a photometry run. This is from a 3 minute exposure in the SCT, camera was the sxv-h9. Guder runs about 6 as/p, and the imager is closer to 0.6 as/p. This image has had a huge stretch.
I think the round stars speak for themselves in this one. I get similar results from 5 minute + exposures with the same configuration.
As for de-focus, you dont really have to worry about that to much. The 9x50 has a HUGE amount of chromatic abberation, and it's very finnicky on focus. Try as you might, with the qhy5 in that setup, you aren't going to get it focussed so well that stars work down to less than a couple pixels. Been there, done that, many times.
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groz
Pooh-Bah
Reged: 03/14/07
Posts: 1288
Loc: Duncan, BC
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Quote:
Thanks groz... I may just be heading in that direction. So their finderscope works by combining the SSAG directly with it? No need to focus, etc?
The 9x50 they provide with the Kwiq uses a helical focus at the objective end, so you focus it on that end, not the camera end. It takes a little fiddling to get it locked down 'close enough' the first time, then you tighten up the lock ring, and never look at focus again.
As has been mentioned in earlier posts, 'not perfect' is ok, but I will say this. If you get the focus 'nearly perfect' with this setup, that's actually as good as you will ever come, it's virtually impossible to get it perfect watching the computer screen. It's easy to tell when it's good enough, you have it pointed at some bright star, example vega, then start working on the focus. When you get it 'good', suddenly close to a dozen little pinpoint stars will start to show up. Now slew it away from the bright one, and you'll see, just about anywhere you point, there's at least 8 or more suitable stars for guiding on.
I've attached an example shot here, this is with the guider pointing at vega, and after getting focus 'good enough'. If memory serves correctly, this was a 1 second exposure. you can see all the halos around the stars, that's the chromatic abberation turning nice pinpoint stars into little smudges, which is in fact good for guiding resolution.
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ebeyonder
member
Reged: 10/16/09
Posts: 92
Loc: Cambridge, MA, USA; Singapore
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Thanks for all the advice! The SV50 was sold so now I am looking at the Kwiq again. Only issue now is cost: the Kwiq with the necessary accessories costs USD$140... add in some rings from SV is an additional $40. That's $180 for a 9x50 finderscope...
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Scopes: Meade ETX-90; LX-90 8"; William Optics FLT-110 with TEC optics; Stellarvue SV80S with LOMO optics
Mounts: Orion Atlas EQ-G mount (Hypertuned); iOptron SmartStar-E GOTO AltAz Mount
Imaging gear: Orion StarShoot Pro v. 2 Deep Space Colour CCD; Meade DSI Pro III Monochrome CCD; DMK 21AU04.AS; Meade DSI I; Celestron Neximage
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Dan G
Carpal Tunnel
Reged: 06/27/06
Posts: 2017
Loc: Minisink, NY, USA
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I purchased an SV50 to use as the guide scope on my ST-402. Surprisingly there was not enough in focus even after I removed all adapters. I had an old Anteres 50mm finder and it came to focus. Not sure if the Starshoot would encounter similar focus issues but it might be worth a call to SV to ask.
Dan in NY
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TV 76, Vixen VC200L, TV NP-127is, Tak FS-60
Astro-Physics 900GTO
ML 8300, Lodestar, ST-402
Tranquility Base Observatory aka "The Shed" by non-tranquil members of the house
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