Been doing some research on how I can reduce the shakiness of my telescope. I would love to fork out a lot of money to get a good mount/tripod but obviously I can't afford that which is why I am looking at alternatives or cheaper ways to reduce the shakiness as I have no plans to upgrade my whole setup for a long time.
I came across this guy who has heavily modified his 130 SLT.
The 130 SLT is a great scope but the only problem with it is stability. I just did a test of where it shakes the most and it is where the dovetail is and the mount itself.
I like the idea of adding a longer dovetail and tube rings as well as a heavy weight or bag of sand.
Are there any tips or advice anyone can give to improve stability (cheaply)?
By the way the original dovetail on the scope has 4 screws like the picture attached.
I've got a Nexstar 102 SLT, and I agree that it has some stability issues! I got this dovetail bar and these rings (obviously you'd have to get the right size rings), and they do certainly help. They also allow me to balance the scope properly with all that 2" stuff on the back!
I should mention that I installed the rings and dovetail bar without having to modify the OTA at all. The original dovetail fits underneath the new one without any modification, so I haven't voided my warranty or risked the optics by fiddling with screws, and I didn't have to rotate the scope (which would have put the finder in a weird spot).
This electric focuser is probably the best upgrade though, because you can completely eliminate the shakes from focusing. No longer really cheap I guess, but it's a highly recommended piece of gear!
The main area of instability remaining for me is actually in the tripod, and then the mount. The mount (AZ in particular) I can't seem to fix, but I'll keep trying. As for the tripod, it has silly plastic caps connecting the legs to the top, and these allow a lot of twist. I fixed that by digging out an old heavy duty aluminium photographic tripod (which is quite sturdy and stable) and using that in place of the stock one. I had to make an adapter so it would fit, and I had to use the whole top of the stock tripod, just with the legs removed.
Anyway, it's now a lot better, but I still feel the wobbles! Below is a photo (before I changed the tripod), also showing the weather, now that the scope is ready for action!
There are cheaper dovetail plates, but I don't think they will fit over the top of the existing bar like the one I got, which is flat on the back and didn't need any modification to go with the rings. I could be wrong, so make sure to measure if you go into Bintel.
BTW, I'd love to be a fly on the wall as you "defiantly" get those rings. (Sorry; couldn't help it).
A lot could be in the tripod too, one thing you could consider is filling the legs of the tripod with sand.
Not sure how portable things would be after though, the weight of that is the only reason I haven't tried it with the EQ-3.
There are cheaper dovetail plates, but I don't think they will fit over the top of the existing bar like the one I got, which is flat on the back and didn't need any modification to go with the rings. I could be wrong, so make sure to measure if you go into Bintel.
BTW, I'd love to be a fly on the wall as you "defiantly" get those rings. (Sorry; couldn't help it).
Went to Bintel yesterday and purchased a Skywatcher 8" dovetail ($35). I was also buying the focal reducer set for $39 but they didn't have any!!! Ordered it and got to wait 2 weeks .
Last night ordered my tube rings from AstroShop (160mm) so once I get them I will install them on the scope and see how much more stable it is. Going to get a bag or sand or weight from bunnings today as well for extra stability.
Hi Stefan and others,
Re 130 SLT stability. I checked mine out,
and I found that upon close inspection, the dovetail is prevented from
sitting right down onto the plate on one side by the cosmetic plastic cover that sits between the scope and the dovetail There is a small gap between the scope and the cover on one side, but not on the other. I removed the cover , and instantly got an improvement in stability.
I removed about 2mm of material from the offending side of the cover
to give clearance.I assume that as they are mass produced, there is a good chance that many will have this problem.
A safety issue I addressed, was that eyepieces easily fall off of the tray, so I have put 1.25mm eyepiece size holes in it. Much better
regards Raymo
Hi Stefan and others,
Re 130 SLT stability. I checked mine out,
and I found that upon close inspection, the dovetail is prevented from
sitting right down onto the plate on one side by the cosmetic plastic cover that sits between the scope and the dovetail There is a small gap between the scope and the cover on one side, but not on the other. I removed the cover , and instantly got an improvement in stability.
I removed about 2mm of material from the offending side of the cover
to give clearance.I assume that as they are mass produced, there is a good chance that many will have this problem.
A safety issue I addressed, was that eyepieces easily fall off of the tray, so I have put 1.25mm eyepiece size holes in it. Much better
regards Raymo
Hey there.
Would you be able to provide a few photos of your explanation as a visual guide would help a lot.
Hi Stefan,
The photos are easy,but I haven't done attachments before, and apparently they have to be smaller than 200kb. I'll see what I can do
tomorrow,
regards raymo
I usually upload photos to imageshack, and then just post links to them. You can also post thumbnails which are small enough for the 200kb limit here but link to the bigger pic if you like.
hi bindibadgi,
Although I have been into astronomy for well over 50yrs.
I have never become very comp. literate, so I have no idea how to post links and thumbnails etc; we'll have to make do with the written word.
Stefan, if you place the scope in a vertical position , and look down to
where it attaches to the mount, you will see the black plastic cover that
is shaped to follow the curve of the scope. On my scope, the end of the cover on the opposite side from the scope securing knob was hard up
against the tube. The end on the same side as the knob had about 1mm
clearance. The end jammed up against the tube prevented the dovetail
from seating fully. If this is still difficult to follow, I suggest that you remove the cover, and see if the stability improves. If it doesn't, then you
obviously don't have this problem. If it does, then you need to remove a little material from the curved ends of the cover, or if you don't want to
do that, just leave the cover off. The cover is easily removed, 2 silver screws facing outward and 2 black ones in the side of the cover at the
opposite side to the black knob. I hope this helps; now I've got to post
one of my problems and see if I can get some help.
regards raymo
. Heaps of good advice there. I will defiantly get the tube rings and will consider the electronic focuser.
(Sorry; couldn't help it).
.
