Click here if you are having trouble logging into the forums
Privacy Policy |
Please read our Terms
of Service | Signup and
Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User
ebeyonder
member
Reged: 10/16/09
Posts: 45
Loc: Cambridge, MA, USA; Singapore
|
|
Hi all,
I'm recently trying to set up my first AP package. Originally I decided on an Orion 80ED on a Orion Sirius Mount with maybe a ST80 guidescope. That seemed like a very feasible set-up for the mount.
However very recently I found this great deal for a WO FLT-110 TEC. I just couldn't pass up on it, so I bought it... but then the weight issues started playing in my mind.
The WO FLT-110 TEC weights 14.3 lbs
Its two rings weigh 1.8 lbs
I intend to image with an Orion Starshoot Pro v 2; that weighs 1.75 lbs
Let's say I do without the diagonal, but there's a 4" focuser on the WO; let's say that weighs 1.5 bs
So that's about 20lbs for the imaging scope.
For the guidescope, I intend to use a ST80; that's 2.4 lbs. I intend to use a Orion Autoguider cam; that's 0.28 lbs
Then I intend to use the ADM Mini system... I don't know what's a good estimate for that... let's just say 1.5lbs
So that's about 24.2lbs now. Then finally add a dovetail plate to the bottom of the main WO scope, plus and minus, I would say I'll have a 25-26lb set-up total for the Sirius Mount, which has a listed weight capacity of 30 lbs.
Now I ought to have realised this when I got the WO FLT-110 TEC, but regretfully the great deal got the better of me and I didn't do the math.
So a few questions:
1. Is this current AP set-up workable?
2. Is it absolutely necessary to upgrade the mount?
3. If I don't upgrade the mount, what defects can I expect? Does anyone have any experience with close to overloading the Sirius mount?
Thank you for any input you might have!
--------------------
Meade ETX-90, ETX-LS, LX-90 8"
|
Midnight Dan
Carpal Tunnel
Reged: 01/23/08
Posts: 2759
Loc: Brockport, NY
|
|
I'll be interested to hear the responses to this since I'm saving up for a Sirius mount and will have a similar load (different scopes).
I think it should be acceptable, but one alternative is to go with an off axis guider instead of a guide scope to conserve weight.
-Dan
--------------------
Scopes: Celestron NexStar 8SE, Orion EON 72mm ED/APO, Orion ShortTube 80
Mounts: NexStar Alt/Az GoTo, Orion Astroview (EQ3) w/single axis drive
Eyepieces: Baader Hyperion 36mm (Aspheric), 21mm 13mm, 8mm, 5mm;
Other: 2x & 3x Barlow, 0.63x Focal Reducer, Dew-not strips, DewBuster controller, SQM Meter
|
Jimmy2K63
Pooh-Bah
Reged: 04/26/09
Posts: 1192
Loc: Kentucky
|
|
All you can do is try it and see, but I think you'll be allright. Just make sure you counterweight it all properly for balance.
--------------------
http://astronomyguy63.blogspot.com/
LXD75 SN6-UHTC
Cave Astrola 10" f/5
Garrett 15x70/FarSight
Canon XS (1000D)
|
FoxK
Carpal Tunnel
Reged: 11/07/07
Posts: 2661
Loc: Cape Cod, MA
|
|
I agree with Jimmy....its hard to give a definitive answer on whether it will be satisfactory. Pushing the mount to its limit in wt. capacity is generally a bad idea if you want consistant good shots. The max weight is usually very optimistic and may give "useable" results but its far from optimum. I think if you want good quality nearly all the time, using 1/2 the max weight is generally a good guideline.
I can tell you through experience that when you have weights close to the max.....BALANCING on the mount is critical!!! I can't overstate that. Its been hard for me to get balance right as it seems that its so dependent on balance that changes beyond the ability of eye to tell can make a difference so I've often had to adjust balance as best I could by eye, and then see if the mount can track a guidestar, and the micromanage adjustment until I see improvement...which way to adjust balance being a 50-50 shot as the changes needed are such that by eye, i can't see the changes to balance i've made due to friction etc.
Regardless, good luck and let us know how you do....I think alotta folks are interested in real data on what scope/mount can be pushed to
--------------------
Orion 80mm ED Apo Refractor
8" Classic Dob (used as Newtonian on CG5 mount)
Meade 70-AZ-A 70mm Guider using PHD
LS60TCaK/B600/C
CG-5 Advanced GT Mount
Nikon D40x with T-Adaptors
Philips SPC900NC(1/4"ccd)& Quickcam 9000(1/3"CMOS)
Imaging Source DMK 21AU04.AS
- click for cloud prediction for Plymouth, MA. area
|
Gregk
Pooh-Bah
Reged: 11/19/06
Posts: 1450
Loc: Gilbert Arizona
|
|
General rule take the recommended maximum and half that amount
unless your pier mounted that may help...I'm struggling now with a CG5 and Backlash. 80ed imaging scope 70mm guide scope rings Stat Shoot Pro DSI guider...near 15 lbs
Regarding an OAG They are nice if your in the Milky Way and even at that I had a real hard time with getting a round star even with the rotation mechanism Maybe I got a bad prism but I sent it back after 3 nights of struggling with it
Just my experience with a 6 inch SCT and 6.3 FR The 80Ed wasn't much better
Greg
--------------------
www.azspaceblog.com/
Orion Star Shoot Pro OSC
Oiron Star Shoot II OSC
Celestron Cg-5 ASGT mount
Celestron ED80 Piggy back with william Optics 66mm APO
Celestron 6" SCT Piggy Back with william Optics 66mm APO
Edited by Gregk (11/06/09 10:25 AM)
|
ebeyonder
member
Reged: 10/16/09
Posts: 45
Loc: Cambridge, MA, USA; Singapore
|
|
Thanks for all your replies 
I suppose I'll just have to try it to find out! I thought of downsizing the guidescope but I'll be imaging from probably light polluted skies, so I figured a 80mm would be optimal for that. Or should I be looking at something smaller?
As for the balancing, this sounds like I need to get one more 11 lbs weight from Orion? The mount only comes with one 11 lb weight. Would two 11 lbs weights be sufficient to balance the set-up?
Thanks again for all the responses!
--------------------
Meade ETX-90, ETX-LS, LX-90 8"
|
knuklhdastnmr
Fumble feet
Reged: 02/24/05
Posts: 4598
Loc: Beerpuddle, Colorado
|
|
Do the counter weights count in the adding up of the pounds on the mount?
--------------------
Knucklhead Astronomer
|
HunterofPhotons
sage
Reged: 04/26/08
Posts: 266
Loc: Rhode Island, USA
|
|
Quote:
Do the counter weights count in the adding up of the pounds on the mount?
If you're asking about the capacity of the mount, then no, the counterweights are not included.
dan
|
Jared
Carpal Tunnel
Reged: 10/11/05
Posts: 2538
Loc: Piedmont, California, U.S.
|
|
Interestingly, I had this exact setup a couple of years ago (aside from the guide scope and camera)! WO/TEC FLT-110 with its dedicated field flattener and a DSLR (later an SBIG ST-2000XCM) all mounted on an Orion Sirius mount. Total instrument weight was just over 25 pounds for me. The saving grace was the 715mm focal length--short enough to keep this from being a serious mistake.
When I was using the DSLR I was taking unguided images. I found that when taking one minute exposures I was throwing out roughly 30% of them if my polar alignment was decent. I decided not to try adding a separate guide scope and camera since I didn't think the mount could handle the extra weight. Instead, I switched to the SBIG camera since it was self guided. I got some pretty decent images, but I still needed to keep the exposure under five minutes or I would be throwing out too many subs. The periodic error with that much weight just wasn't smooth enough for arbitrary exposure lengths. Still, it was quite workable at five minutes and I was pretty happy considering the price of the mount. I expect you will have a lot of fun with it, so definitely give it a shot!
By the way, I upgraded the mount to a Losmandy GM-8 and found that I didn't really get any better results! The two mounts have similar capacities, but I expected the better quality of the Losmandy to shine through--it didn't. It wasn't until I moved to a really expensive/higher capacity mount (an Astro-Physics Mach1) that the mount stopped being the limiting factor in my image quality.
You're going to love that FLT-110, I suspect. I have enjoyed mine so much I have actually taken the time and trouble to "improve" it even further--with a 3" FeatherTouch focuser and some rework on the light baffles. The 4" WO focuser is pretty good--though it's really a 3"; WO is the only company that measures focuser size by outside diameter rather than inside diameter--but it just wasn't up to holding my current camera with the field flattener. I don't expect you to have any problems with the cameras you are proposing using.
Best of luck!
--------------------
- Jared Willson
- TMB 152 f/8 Apochromat
- Fluorostar FLT-110 w/ TEC optics
- Stellarvue SV80S
- Astro-Physics Mach1 GTO
- Takahashi Teegul SP Mount
- STL-11000
|
Dan G
Carpal Tunnel
Reged: 06/27/06
Posts: 1761
Loc: Minisink, NY, USA
|
|
Based on Jared's comments you might reconsider your guide scope. It's not just the extra weight. In fact with the addition of a guide scope you are moving the center of gravity for the scope side of the mount further away from the polar axis. Either an SBIG with a guiding chip or maybe a 50mm finder scope mounted on the 110 with minimal - but rigid - connections.
Dan in NY
--------------------
TV 76, Vixen VC200L, TV NP-127is
EM-200, NJP
ML 8300, ST-402
Tranquility Base Observatory aka "The Shed" by non-tranquil members of the house
|
ebeyonder
member
Reged: 10/16/09
Posts: 45
Loc: Cambridge, MA, USA; Singapore
|
|
Thanks for all the suggestions. Indeed I think I'll try a different guidescope. I am thinking of the KWIG auto guider - essentially a 50mm finderscope. One potential problem is that I may be imaging in light polluted skies. With a smaller guidescope, would I have more difficulty finding suitable stars? Thank you.
--------------------
Meade ETX-90, ETX-LS, LX-90 8"
|
FoxK
Carpal Tunnel
Reged: 11/07/07
Posts: 2661
Loc: Cape Cod, MA
|
|
GregK.....keep experimenting...especially with backlash compensation settings on the cg5...try different numbers...i'm not at my house with my cg5 atm so i can't tell u what i have mine set at but it did help. I have a similar setup...cg5 and an Orion 80mm ED and i have it set up so i can go hours now without star trailing
--------------------
Orion 80mm ED Apo Refractor
8" Classic Dob (used as Newtonian on CG5 mount)
Meade 70-AZ-A 70mm Guider using PHD
LS60TCaK/B600/C
CG-5 Advanced GT Mount
Nikon D40x with T-Adaptors
Philips SPC900NC(1/4"ccd)& Quickcam 9000(1/3"CMOS)
Imaging Source DMK 21AU04.AS
- click for cloud prediction for Plymouth, MA. area
|
|
8 registered and 5 anonymous users are browsing this forum.
Moderator: Charlie Hein, knuklhdastnmr
Print Thread
|
Forum Permissions
You cannot start new topics
You cannot reply to topics
HTML is disabled
UBBCode is enabled
|
Thread views: 256
|
|
|
|
|
|
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
