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What's on YOUR GM8?

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#1 Cotts

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Posted 01 December 2020 - 06:45 PM

I will acquire a Losmandy GM8 Gemini 1 tomorrow.  My plan is to use it for autoguided AP with DSLR and lenses from 10mm to 400mm (the latter is the AstroTech Quad APO refractor...).  This is a major downsizing from an AP Mach 1 for me but I'm trying to recover some $ from my gear for other projects, some non-astro.....  Note that AP will only occupy 1 out of every 5 nights on average with visual being pre-eminent in my life with an 8-inch MakNewt on a Discmount DM6....  

 

Curious about what folks are putting on their GM8 (or what they did when they had one...)

 

Dave

 

 


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#2 ismosi

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Posted 01 December 2020 - 07:05 PM

I had my Televue NP-101 on the GM-8. I own neither one now, though.



#3 rk2k2

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Posted 01 December 2020 - 08:02 PM

Not an 8 but a 811: Sigma 150-600mm/ lens on Nikon or Olympus PL7. VC200l,  an ST120 (rarely), and starting Thursday, an FRA400.



#4 Sandy Swede

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Posted 01 December 2020 - 08:37 PM

Is the weight capacity for yours 30 or 40 lbs?  The website for the current production GM8 G2 lists these as a range for AP.  In any event, the heaviest scope riding on my GM811G is the Intes Micro 815 8" Mak at 23 lbs.  However, the OTA is 24" and a tad over 10" in diameter.  So more bulky than heavy.  I bought it used and it came with a V dovetail.  Immediately swapped in a D dovetail plate.  Much more stable now.



#5 Cotts

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Posted 01 December 2020 - 09:32 PM

Is the old GM8 the same as this GM8-11?  Then there is the G11...  Are we talking about 3 mounts here?

 

Dave



#6 rkaufmann87

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Posted 01 December 2020 - 10:16 PM

I have an AT130EDT triplet on mine. Here is a picture:

GM8 and AT130EDT


#7 jonnybravo0311

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Posted 01 December 2020 - 10:46 PM

Is the old GM8 the same as this GM8-11?  Then there is the G11...  Are we talking about 3 mounts here?

 

Dave

Yes... three mounts.

 

GM8G: 30-40 pounds capacity

GM811G: 50 pounds capacity

G11G: 60 pounds capacity

 

I only know this because I started looking at the Losmandy offerings today :)


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#8 weis14

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Posted 01 December 2020 - 10:53 PM

Yes... three mounts.

 

GM8G: 30-40 pounds capacity

GM811G: 50 pounds capacity

G11G: 60 pounds capacity

 

I only know this because I started looking at the Losmandy offerings today smile.gif

This is correct.  The GM811 is the G11 RA assembly paired with the G8 declination assembly.  Since the RA assembly is the important one for tracking, I find it to be more similar to the G11 in capability than the G8, especially with the HD tripod.  

 

I'll also mention that my GM811 actually says "G11" on the side, which is likely due to the fact that the model number is part of the RA assembly and I doubt that Losmandy is making different housings for the G11 and G811.


Edited by weis14, 01 December 2020 - 10:54 PM.

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#9 Maxtrixbass

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Posted 02 December 2020 - 11:11 PM

When I tell people I'm doing deep sky AP on a GM8 with an 8" newtonian most  think I'm crazy. It does work, but the 24# and fairly long (F6) tube are pushing the mount pretty hard. It does work rather well, but sits on the fringe. A stiff breeze and its struggling.

 

Still, it does say much that the mount can do it at all. It does help that it sits on a cement pier.



#10 Jaimo!

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Posted 02 December 2020 - 11:16 PM

Dave, 

I just picked up a second hand GM8 with Gemini 1 just a few weeks ago and I have not yet used it.  I plan to watch this thread with great interest.  In the near future, I hope to mount my Z61, Z81 and MK-67 for a light imaging / portable rig.  Just yesterday I received a RJ9 to USB cable that will allow my ASIair or laptop to run the mount rather the the "less than user friendly" Gemini 1 hand controller.

 

Happy New Mount Day!

Jaimo!



#11 SonnyE

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Posted 03 December 2020 - 02:31 AM

I put my Orion ED80T CF with a lot of trimmings on my GM8 Dec assembly.

Which is attached to a G11G RA head.

And I chose to get the HD tripod.

 

GM811GHD, Gemini II controller. Nirvanas for me.

 

You can tap into a group with an amazing amount of experience, expertise, and repair of Losmandy Mounts, Gemini I and II controllers, and Brian who works as support for Losmandy.

 

This video really explains where Scott Losmandy is today with the mounts he's built since the 1980's, when he began. It's quite impressive.

 

But another thing that was more important to me was the ability to really customize my new mount to fit my needs.

I have to set-up, and remove my mount daily, Ma Ma's rules, the mount comes in the house when not in use.

I decided I wanted a Portable Pier as my mount. And I worked out I needed manageable "chunks", since well, Ma Ma's rules, and I'm an old fart. I can make several trips, but I can't carry the weight I once could.

So my entire mount is very easily dismantled, and reassembled, with no more than loosening and tightening hand screws, and minimal wiring connections. (3 on top, 3 on the ground end.)

 

So my Orion ED80T CF rides on MY GM8 (11G HD).

 

Once, I did put together my Nikon D3400, Tamron 150-600 mm, battery eliminator, on a Vixen bar, and took pictures of the last comet. It worked phantasmagorical !

But I don't know if the Gemini I has comet tracking.

Still, I bet it will work great for what you have in mind, Casual Astrophotography. 

Sounds very enjoyable!


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#12 Eric P

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Posted 03 December 2020 - 10:24 AM

I used a Meade 152ED with the GM8 Gemini, LW tripod and tripod extension.  Good visual platform even with the big Meade.



#13 Raginar

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Posted 03 December 2020 - 10:36 AM

I will acquire a Losmandy GM8 Gemini 1 tomorrow.  My plan is to use it for autoguided AP with DSLR and lenses from 10mm to 400mm (the latter is the AstroTech Quad APO refractor...).  This is a major downsizing from an AP Mach 1 for me but I'm trying to recover some $ from my gear for other projects, some non-astro.....  Note that AP will only occupy 1 out of every 5 nights on average with visual being pre-eminent in my life with an 8-inch MakNewt on a Discmount DM6....  

 

Curious about what folks are putting on their GM8 (or what they did when they had one...)

 

Dave

Gemini-1 is... special.  If you like retro gaming; it'll be fine and you can use ASCOM.  Other than that, my ol' GM8 was what I used it for too.  It's really good!



#14 jonnybravo0311

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Posted 03 December 2020 - 10:54 AM

This may be a dumb question, but here goes :)

 

How are you polar aligning?

 

When looking at the Losmandy mounts, it appears that a polar scope is an optional accessory. Errrr... ok... is the expectation that you already have some solution like the polemaster or a guide scope and camera or an OAG that you'd use via a connection through the Gemini controller?

 

With a $300 asking price for a polar scope, it seems rather more economical to pick up the polemaster or something like the WO 32 guide scope and ZWO 120mm mini.

 

Am I missing something (probably)?



#15 rk2k2

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Posted 03 December 2020 - 11:38 AM

 that you'd use via a connection through the Gemini controller?

Don't know about that capability.  Although there is a USB port that I assume can be used to communicate with Gemini-2 (I've only used ethernet), my understanding is the other USB- A port on Gemini-2 only provides power and has no data capability.  So a USB connection from a camera (as with my Polemaster) has no way to connect to the Gemini-2.  Thus, a Polemaster (or guide camera) has to be connected to a PC where the appropriate app (PHD 2, SharpCap, Polemaster software, etc)  is running.
 

I'll add, Gemini-2 has a PAC (Polar Alignment Correction) feature that allows 'better' PA as long as you're within 1 to 2 degrees to begin with.  You go through 'modeling' (think of that as an 'enhanced' star alignment similar to a 1, 2, 3, 4, .... star alignment).  As you progress through the modeling (adding stars), eventually you get the option for 'PAC'.  In PAC, Gemini-2 goes through a routine of going to stars, which you use the AZ and EL knobs on the mount to center those stars as observed through an eyepiece or main imaging camera.  As I recall, you should go through an iteration of at least 6 or 7 stars.

 

If that makes sense, you should be able to realize you don't NEED a PA scope or PA camera like Polemaster.  Those just make PA more accurate, easier, and quicker.


Edited by rk2k2, 03 December 2020 - 12:21 PM.


#16 weis14

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Posted 03 December 2020 - 12:17 PM

This may be a dumb question, but here goes :)

How are you polar aligning?

When looking at the Losmandy mounts, it appears that a polar scope is an optional accessory. Errrr... ok... is the expectation that you already have some solution like the polemaster or a guide scope and camera or an OAG that you'd use via a connection through the Gemini controller?

With a $300 asking price for a polar scope, it seems rather more economical to pick up the polemaster or something like the WO 32 guide scope and ZWO 120mm mini.

Am I missing something (probably)?


I use a Polemaster. It works great and I've found it much more convenient than a polar scope. I do this even for visual.

#17 Cotts

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Posted 03 December 2020 - 12:58 PM

Update on my GM8.  It's level 4, ver 1.05.  Early 2000's

 

Hand paddle menu manipulation is clunky, to say the least...but all the slews work.  I did an indoor 'fake' alignment on a star (Albireo) this morning and it seemed to point to stuff roughly where it should be - M57, Deneb etc......

 

Really good news is that it works perfectly with my Sky Safari Pro which I will use for all target selection in the field.  I had to go to "that box" with assorted cables in it and,  lo and behold, a nice 2m coily serial cable was there.  (Pro Tip: don't throw that kind of stuff out!!!) Did go-to's from the touch screen and from observing lists - perfect!  Also can use the touch screen for +/- Dec and +/- RA movement.   Once an initial star align is done through the hand paddle I'll use the Sky Safari for the rest of the session.

 

 

I am now taking a lunch break from disassembling and cleaning all the bearings for both axes.   Have to go to the hardware to get some grease that was recommended on the Losmandy io group.... ---> Synco Chemical - SuperLube with Syncolon (Teflon). 

 

The polar scope is a backbreaker - it's the one with a picture of Cas and UMa with some little tics for Polaris and a couple of other stars....  I'll look into a Polemaster.....  I got spoiled with the right angle polar scope on my Mach 1....

 

Two issues:  1.  I updated the date and time, lat and long etc. but these were not remembered when I turned it off for a few minutes and turned it back on...

 

2.  I put my AstroTEch 65 + 50mm finder/autoguder on the mount and the lightest counterweight (5 pounds est.) slid all the way up the shaft is still a bit too heavy!!  Considering I will be using even lighter tackle like a DSLR and 200mm lens how shall I balance the system?

 

Progress reports as they come...

 

Dave


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#18 astrohamp

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Posted 03 December 2020 - 01:58 PM

No Polar Scope required,

 

 

Spent decades pushing my ol' 8 with a Televue Pronto, and Antares 152 f/6.5 refractor, now going to overload it a bit with a de-forked Meade LX6 10" cassegrain.

I decided to upgrade my GM8 way past expired (reticle markings) polar scope with a small format cmos camera and C-mount camera lens.  Put into rings and guide scope mount on the 6" OTA SharpCap polar align freeware was much easier than doing the 'Losmandy Limbo'.  Now the OTA camera (4k) provides the polar plate solve image for SharpCap Pro with nary a problem, even through (after Fall) naked trees. 



#19 Jaimo!

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Posted 03 December 2020 - 02:11 PM

 

Two issues:  1.  I updated the date and time, lat and long etc. but these were not remembered when I turned it off for a few minutes and turned it back on...

 

That would indicate that the internal battery (CR 2354 3V) in the Gemini needs to be replaced.  HERE are instructions.

 

This is a good sight for Gemini issues:  https://gemini-2.com/, they have a sub heading for Gemini 1.



#20 Cotts

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Posted 03 December 2020 - 04:42 PM

That would indicate that the internal battery (CR 2354 3V) in the Gemini needs to be replaced.  HERE are instructions.

 

This is a good sight for Gemini issues:  https://gemini-2.com/, they have a sub heading for Gemini 1.

Thanks!  Same batteries as my guitar tuner....  

 

Dave



#21 Cotts

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Posted 03 December 2020 - 04:45 PM

cleaning Dec axis has gone well.  I have ordered the grease on Amazon but it will be a couple of weeks...  Christmas rush + covid..

 

I do not like buying anything from Bezos - these days are for buying from local businesses.  But none stock this grease.  There are stores in Toronto but I'm not driving 400km round trip for a $20 item...

 

Dave



#22 Jaimo!

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Posted 03 December 2020 - 08:53 PM

Thanks!  Same batteries as my guitar tuner....  

 

Dave

Mine takes a 9V...

 

Boss TU-3

 

I hope over/before the Christmas break that I will get this piece of kit up and running.



#23 KNak

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Posted 03 December 2020 - 09:23 PM

cleaning Dec axis has gone well.  I have ordered the grease on Amazon but it will be a couple of weeks...  Christmas rush + covid..

 

I do not like buying anything from Bezos - these days are for buying from local businesses.  But none stock this grease.  There are stores in Toronto but I'm not driving 400km round trip for a $20 item...

 

Dave

 

Not even your Home Hardware?  That's where I bought mine locally once upon a time.



#24 Wildetelescope

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Posted 04 December 2020 - 09:52 AM

Update on my GM8.  It's level 4, ver 1.05.  Early 2000's

 

Hand paddle menu manipulation is clunky, to say the least...but all the slews work.  I did an indoor 'fake' alignment on a star (Albireo) this morning and it seemed to point to stuff roughly where it should be - M57, Deneb etc......

 

Really good news is that it works perfectly with my Sky Safari Pro which I will use for all target selection in the field.  I had to go to "that box" with assorted cables in it and,  lo and behold, a nice 2m coily serial cable was there.  (Pro Tip: don't throw that kind of stuff out!!!) Did go-to's from the touch screen and from observing lists - perfect!  Also can use the touch screen for +/- Dec and +/- RA movement.   Once an initial star align is done through the hand paddle I'll use the Sky Safari for the rest of the session.

 

 

I am now taking a lunch break from disassembling and cleaning all the bearings for both axes.   Have to go to the hardware to get some grease that was recommended on the Losmandy io group.... ---> Synco Chemical - SuperLube with Syncolon (Teflon). 

 

The polar scope is a backbreaker - it's the one with a picture of Cas and UMa with some little tics for Polaris and a couple of other stars....  I'll look into a Polemaster.....  I got spoiled with the right angle polar scope on my Mach 1....

 

Two issues:  1.  I updated the date and time, lat and long etc. but these were not remembered when I turned it off for a few minutes and turned it back on...

 

2.  I put my AstroTEch 65 + 50mm finder/autoguder on the mount and the lightest counterweight (5 pounds est.) slid all the way up the shaft is still a bit too heavy!!  Considering I will be using even lighter tackle like a DSLR and 200mm lens how shall I balance the system?

 

Progress reports as they come...

 

Dave

I have a digital drive version that is older than yours.   I have done DSO imaging guided and unguided with my Astrotech EDT 80 mm.  it works for my level of pickiness.  I have done unguided short duration DSO imaging with my 6 inch mak.  I have done planetary and lunar imaging with my C8.  I have done visual with my 127 mm F8 triplet and found it to be a very satisfactory experience(I am picky about wiggles when focusing).  I mount my GM8 on an old HD tripod.  That makes a big difference with the larger scopes.  The DSO imaging with the 80 mm was on the LW tripod and it worked fine.   Guiding with the Digital drive was.... Different.  Since the hand controller plug does double duty as the guide camera connection, you have to make sure you manually set the slew rate to a low value, otherwise your guiding does very strange thingslol.gif.  Other than that, it worked reasonably well.  Cleaning and remeshing the gears is good!  So is Polemaster, which I use.   

 

I like all my Losmandy mounts, but to be clear, the GM8 is NOT a Mach I:-).   As long as you understand that I think you will be very happy. For the image scales you are talking about, it should be more than sufficient.   For visual, I think it will even handle your MakNewt (of which I am very jealous:-) depending how well you balance it and your sensitivity to wiggles.  

 

Have fun!

 

JMD



#25 Raginar

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Posted 04 December 2020 - 09:59 AM

Update on my GM8.  It's level 4, ver 1.05.  Early 2000's

 

Hand paddle menu manipulation is clunky, to say the least...but all the slews work.  I did an indoor 'fake' alignment on a star (Albireo) this morning and it seemed to point to stuff roughly where it should be - M57, Deneb etc......

 

Really good news is that it works perfectly with my Sky Safari Pro which I will use for all target selection in the field.  I had to go to "that box" with assorted cables in it and,  lo and behold, a nice 2m coily serial cable was there.  (Pro Tip: don't throw that kind of stuff out!!!) Did go-to's from the touch screen and from observing lists - perfect!  Also can use the touch screen for +/- Dec and +/- RA movement.   Once an initial star align is done through the hand paddle I'll use the Sky Safari for the rest of the session.

 

 

I am now taking a lunch break from disassembling and cleaning all the bearings for both axes.   Have to go to the hardware to get some grease that was recommended on the Losmandy io group.... ---> Synco Chemical - SuperLube with Syncolon (Teflon). 

 

The polar scope is a backbreaker - it's the one with a picture of Cas and UMa with some little tics for Polaris and a couple of other stars....  I'll look into a Polemaster.....  I got spoiled with the right angle polar scope on my Mach 1....

 

Two issues:  1.  I updated the date and time, lat and long etc. but these were not remembered when I turned it off for a few minutes and turned it back on...

 

2.  I put my AstroTEch 65 + 50mm finder/autoguder on the mount and the lightest counterweight (5 pounds est.) slid all the way up the shaft is still a bit too heavy!!  Considering I will be using even lighter tackle like a DSLR and 200mm lens how shall I balance the system?

 

Progress reports as they come...

 

Dave

Use sharpcap for polar alignment if you're putting the guidescope on it.  I think there is a battery to keep the time/date/etc; it probably needs to be replaced.


Edited by Raginar, 04 December 2020 - 10:00 AM.



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