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Re: GM8 with Televue Genesis and 50mm guider: piggyback or side-by-side?


Feb 17 2:30 AM

 


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#48102 Feb 17 2:30 AM

Hello everyone, I started to ask this question in another thread, but thought it would be better to stay on-topic and start a new one for it here. Hope that's ok.



I currently have a Televue Genesis SDF mounted on a Losmandy GM8. Thanks to Bill and Bud here, we've ascertained my GM8 is using the old style dovetail which is no longer sold.



I recently bought a Borg 50mm guider with the view of getting more into imaging and am considering different ways to mount it on or alongside the Genesis. I'd also like some way to mount a DSLR with a basic lens on there too.



I realise Bud and Bill have already made some suggestions in my GM8 dovetail thread, but I'd love to hear more from them, or anyone else regarding this second question.



The two main options are piggyback or side-by-side.



My Genesis has the clamshell mount with two channels for mounting accessories, so the most obvious suggestion would be to piggbyack the Borg on one and the DSLR on the other. Do you think this would work fine, or would there be flex issues along with too much strain on the Genesis-to-Losmandy plate connection?



Alternatively I could replace the clamshell for tougher rings like the Televue MRS-4000 or a set from Parallax - any views on which is better? I could mount a rail onto these for the guider, although I'm not sure where the DSLR would go. The MRS-4000 still has channels for accessories, but would hanging a DLSR off the side while having a Guider on top be a good idea? I guess it could go on top of the rings for the Borg, but again is a triple-piggtback a good idea?



The other route is using a side-by-side plate, but please remember I have the older GM8 dovetail, so unless I can find an old-style dual saddle for it, there's going to be some reinvestment required.



Due to a mistaken order, I actually already have a Losmandy DSBS dual saddle and a DUPS plate here, although they may be returned if I won't use them. I'd of course need another DUPS for the Genesis, and either a GM8SPD or G11SP in order to accommodate D-series plates on the GM8.



I'd be happy to go down the side-by-side route, but I'm quite shocked by the weight of the DSBS. I fear a DSBS with two DUPS, a Genesis, Borg and DSLR will be too much load for the GM8. Maybe the V-series is the answer in this scenario, or one of ADM's D / V series dual saddles.



Any thoughts or suggestions much appreciated!



Many thanks,



Gordon



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#48104 Feb 18 5:36 AM

I use gm8,g11 tripod and 12 inch extension, side by side bar, stellarvue 80mm NHNG (8 pounds) and stellarvue 60mm, Orion ssag and sbig st402 as my baseline system. Gm8 can handle this. Have mounted 60mm guide scope and 80mm on bar using D style. I seem to have desired results more often with the bar approach.



Ke



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#48105 Feb 18 12:47 PM

With such a light guide scope I would piggy back. Side by side has the benefit of keeping the center of gravity lower for heaver guide scopes on lighter mounts. But it's a good deal more difficult to balance, plus there are more areas for flexure to creep in. Piggy back is simpler and easier to balance, but it creates a higher center of gravity and thus requires more counterweight to properly balance.



With my AT106LE and 50mm Guider I piggy back. When I had a CG-5 and a 8" SCT with a 80mm guider I did side by side to keep the load lower on the mount.



I would recommend Piggy back pretty much 90% of the time if your mount will support it. And yours will with the light weight guider you'll be using.



Are you going to be using the Genesis for photography with the DSLR or a different camera? If you're using it with the DSLR then there's no need to mount the DSLR separately. Use the Genesis as the guide scope and place the DSLR on top. When shooting with the DSLR through the genesis put the 50mm on top for guiding and the DSLR on the back of the Genesis. That gives you the best of both worlds without having to go to a side by side setup. Really the only reason to use the side by side setup is if you plan on taking an image through the Genesis as well as through a camera lens. But you only mentioned the guide camera and the DSLR so I'm guessing this might not be the case.



Jared



--- In Losmandy_users@yahoogroups.com, "cameralabs" contact@...> wrote:

>

> Hello everyone, I started to ask this question in another thread, but thought it would be better to stay on-topic and start a new one for it here. Hope that's ok.

>

> I currently have a Televue Genesis SDF mounted on a Losmandy GM8. Thanks to Bill and Bud here, we've ascertained my GM8 is using the old style dovetail which is no longer sold.

>

> I recently bought a Borg 50mm guider with the view of getting more into imaging and am considering different ways to mount it on or alongside the Genesis. I'd also like some way to mount a DSLR with a basic lens on there too.

>

> I realise Bud and Bill have already made some suggestions in my GM8 dovetail thread, but I'd love to hear more from them, or anyone else regarding this second question.

>

> The two main options are piggyback or side-by-side.

>

> My Genesis has the clamshell mount with two channels for mounting accessories, so the most obvious suggestion would be to piggbyack the Borg on one and the DSLR on the other. Do you think this would work fine, or would there be flex issues along with too much strain on the Genesis-to-Losmandy plate connection?

>

> Alternatively I could replace the clamshell for tougher rings like the Televue MRS-4000 or a set from Parallax - any views on which is better? I could mount a rail onto these for the guider, although I'm not sure where the DSLR would go. The MRS-4000 still has channels for accessories, but would hanging a DLSR off the side while having a Guider on top be a good idea? I guess it could go on top of the rings for the Borg, but again is a triple-piggtback a good idea?

>

> The other route is using a side-by-side plate, but please remember I have the older GM8 dovetail, so unless I can find an old-style dual saddle for it, there's going to be some reinvestment required.

>

> Due to a mistaken order, I actually already have a Losmandy DSBS dual saddle and a DUPS plate here, although they may be returned if I won't use them. I'd of course need another DUPS for the Genesis, and either a GM8SPD or G11SP in order to accommodate D-series plates on the GM8.

>

> I'd be happy to go down the side-by-side route, but I'm quite shocked by the weight of the DSBS. I fear a DSBS with two DUPS, a Genesis, Borg and DSLR will be too much load for the GM8. Maybe the V-series is the answer in this scenario, or one of ADM's D / V series dual saddles.

>

> Any thoughts or suggestions much appreciated!

>

> Many thanks,

>

> Gordon

>







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#48110 Feb 19 1:01 PM

Thanks Ke and Jared,



Ke, it's reassuring to hear of heavier loads being supported by a GM8. Maybe I'm underestimating what it's capable of.



Jared, I'll be imaging with a DSLR through the Genesis, and also with standard camera lenses, although not at the same time - so yes, I could swap the guide scope for the DSLR and lens, and use the Genesis for guiding. Ideally I'd like to leave the guider on the guidescope at all times, but realise this may not be possible with a piggyback solution.



But I think a piggyback is still the way to go at the moment



So the only question now is what piggyback solution to use...



I could mount accessories onto the proprietary channels in the Televue clamshell, but for stability and strength, I think it would be better to swap this for two new rings and an accessory bar. Is this a better idea?



If so, does anyone have any view of the Televue MRS-4000 versus a pair of Parallax rings, and if the latter, what bar would you recommend for accessories on top?



www.astronomics.com/main/product.asp/catalog_name/Astronomics/category_name/7KNU5BBG60WE8LQ67W7UG99532/product_id/MRS4



www.parallaxinstruments.com/ring.htm



Many thanks everyone!



Gordon



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#48115 Feb 20 5:09 PM

All rings are pretty much equal, provided they hold the OTA tightly.



The TV ones look nice but they seem expensive to me! I use the set that came with my AT106LE and they're more than adequate for my needs. Seem to hold everything quite rigidly.



My setup is very similar to yours. On the AT106LE I have a D dovetail on the bottom and a V dovetail on the top. The D mounts to my G11 and the 50mm guider mounts to the V rail on top of the 106. I also have a tripod head mounted to a V clamp that can also mount to the V rail and I can then guide with the 106.



You can also pickup a universal finder mount and attach the guider via a finder shoe. That way you can mount the DSLR on top of the TV and place the guider where the finder would normally reside. Hopefully that makes some sense. I considered going this route because with both dovetails the fit is a little tight in the case. But I decided the current setup with the V rail gives me the most flexibility and is the most rigid way to attach the guider.



Jared



--- In Losmandy_users@yahoogroups.com, "cameralabs" contact@...> wrote:

>

> Thanks Ke and Jared,

>

> Ke, it's reassuring to hear of heavier loads being supported by a GM8. Maybe I'm underestimating what it's capable of.

>

> Jared, I'll be imaging with a DSLR through the Genesis, and also with standard camera lenses, although not at the same time - so yes, I could swap the guide scope for the DSLR and lens, and use the Genesis for guiding. Ideally I'd like to leave the guider on the guidescope at all times, but realise this may not be possible with a piggyback solution.

>

> But I think a piggyback is still the way to go at the moment

>

> So the only question now is what piggyback solution to use...

>

> I could mount accessories onto the proprietary channels in the Televue clamshell, but for stability and strength, I think it would be better to swap this for two new rings and an accessory bar. Is this a better idea?

>

> If so, does anyone have any view of the Televue MRS-4000 versus a pair of Parallax rings, and if the latter, what bar would you recommend for accessories on top?

>

> www.astronomics.com/main/product.asp/catalog_name/Astronomics/category_name/7KNU5BBG60WE8LQ67W7UG99532/product_id/MRS4

>

> www.parallaxinstruments.com/ring.htm

>

> Many thanks everyone!

>

> Gordon

>



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#48130 Feb 22 11:00 PM

Thanks for your help Jared!



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