Celestron Nexstar SLT102 as a grab-n-go

[dph1nm]

For 35 years or so I have owned a 8.5" F6 Newtonian (now on an HEQ5 Goto mount). Unfortunately, dragging this rather heavy beast out of the house and setting it up for an hour or so's observing in my light polluted garden was just getting too much, so I thought it was time to have a new, more portable scope (being a deep-sky fan, what I really wanted was a 16" Lightbridge, of course, but these are neither light nor portable!). The telescope had to offer something different from the Newtonian - so I settled on a wide field refractor. Given it would have to have a small aperture to keep the weight down, it also had to be cheap (I can't see the point of paying hundreds for a 3-4inch scope - they just don't have the light grasp for me). Having experience of the HEQ5 Goto, I also wanted a Goto mount (yeah, I know, star-hopping is good for the soul, but ...).

The Celestron Nexstar SLT102 leaped out as the ideal candidate in all these respects, so thanks to Rother Valley Optics I now have one. Despite it being an F6.5 scope, I have no issues with chromatic aberration (for wide fields I don't see this as a problem) - bright stars have a purple rim one side of focus and green on the other, but these dissappear when in focus.

1/650 sec, afocal through 32mm eyepiece

Holmes, 15x8sec, afocal through 32mm eyepiece

So, after a few weeks, how has it shaped up? Well, I love it! I can lift it with one hand, it gives sharp images over 2deg with a 32mm eyepiece, and the Skyalign set-up is just wonderfull. One can be lined up and 'Going-To' in just a couple of mins. No more lying on the floor peering up polar scopes to try and align the HEQ5! My skies are badly light polluted but it showed M81/2 without any problem, and the first night out I even spotted M33, which I have never seen reliably at the larger scale of the 8.5 inch.

I do afocal photography with an old Olympus 2020z (so lots of 16sec or less exposures stacked), so I hoped the alt-az mount wouldn't be too much of a problem, and so far this seems to be so. I have managed stacks amounting up to 15min. Tracking seems good, but with occassion glitches where it just gives up for a few secs. Out of about 70 16sec frames on one target I lost only 3-4 due to tracking issues.

Having read up about the scope on the www I bought a motor focusser to go with it - to be honest this isn't necessary at low powers. Yes, the mount is light-weight and vibrates if you kick it - so don't! I have taken to using it (tripod legs retracted) on top of a patio table - works fine and just ends up the right height for my eyes.

The scope is attached to the mount with a very short Skywatcher type dovetail - I had hoped to replace this with a longer one in order to help balance for 2in eyepieces etc (that is the next upgrade!), but it is bolted onto the tube. Replacing it would need the lens out - no thank you. To detatch it you might get away with just removing the focusser assembly and tipping the bolts out. I believe it might be possible to use the longer dovetail by bypassing the current one entirely using mounting rings.

All in all, this is an amazing piece of kit for under 300 pounds, and it will definitely be heading to darker skies in the back of the car, something I would never attempt with the Newtonian.

NigelM

3min stacked on M57, afocal 32mm eyepiece at about 6 arcsec/pixel

[The Warthog]

Nice review, thanks. And I agree with you about goto.

[SteelRat]

Good stuff Nigel 8) I really do love my little SLT mount. Yes starhopping is good for the soul...

...GOTO is good for the back and knees

[Whippy]

Nice review Nigel, those SLT's look pretty good for the money .

Tony..