A commenter asked about my piggyback imaging setup, so I took a photo (with my phone) tonight that shows how I hook everything up. If you click to the flickr page (just click on the image) I have labels on most of the parts.
September 1, 2011
December 16, 2009
Today, a package from Yuri in California arrived at my house. What was in it?
Well, it was well wrapped in bubble wrap…
It is, indeed a telescope:
It’s a 150mm Maksutov Cassegrain telescope, to be precise. Tonight is supposed to be decently clear and so I’m hoping to put check it out tonight. This should be a fantastic planetary and lunar scope! I’m very excited!
October 17, 2009
A bit over a year ago, I bought a Meade 1244 motorized focuser unit and adapted it for use with my LXD-75 SN-8 telescope. The 1244 unit (that I got off of eBay) is designed for a completely different scope (the ETX series), but I was convinced I could make it work with my stuff and so I got one cheap. As far as I know, there is no model specifically designed for my scope. Here’s how I did the adaptation:
Adapting the focuser shaft
After disassembling my focuser, I unscrewed the left knob from the shaft. After measuring the threads on that side of the shaft, I tapped a brass rod that I had cut to length (about an inch and a quarter) so that I could thread it onto the shaft. Once I made sure that it screwed on well, I added some Loctite Blue and screwed it in. I don’t expect it to ever come apart, but if it did, it’ll be easy for me to reattach it. I also flattened one area on the rod so that a gear set screw will have a place to hold on.
Now that I have finished the rod, I need to attach the gear that came with the 1244 focuser. The rod that I purchased had the same outer diameter as the inside of this gear. I can’t tell you what it was because I don’t remember, but I just took the gear to the hardware store and found a rod that fit nicely. Before attaching the gear, you have to slide on a plastic piece that came with the focuser first. make sure you have it facing the right way. You can spin it around, but you can’t flip it once it’s on there. After sliding the plastic piece on, I slid on the gear and then tightened the set screw. Incidentally, you’ll need a .050 hex wrench to tighten it. The 1244 comes with one.
Reassembling the focuser
Now that the shaft is complete, it’s time to reassemble the focuser. You might take this time while everything is disassembled to clean out the grease and gunk and relubricate the focuser. I added a bit of teflon tape to cut down a bit on focuser shift and I used a light coating of white lithium grease to relube everything. Next I place the focuser shaft into position:
Next, I added the cover over the “gearbox” area.
Before I put the screws on, I add the custom bracket that I made. I made the bracket from a piece of aluminum that I carefully cut to size, bent and then drilled 5 holes. To make sure the holes were in the right place, I drilled through the gearbox cover so that the four screwholes would match up. The other hole, for mounting the focuser, I marked through the screwhole in the focuser with a pencil lead (it’s pretty thin) and then drilled. Here’s the custom bracket:
While you hold the bracket in place, you screw in the four screws through the bracket and the gearbox cover into the focuser. While I start to screw them in with my cordless drill, it’s important not to tighten them too much, so I finish by hand. As you tighten them, you make it more difficult to turn the gear and it presses harder on the focuser tube. You want the movement to be nearly effortless, so make sure you test as you tighten by hand.
Attaching the Motor
It’s now time to attach the motor. I place it over the shaft and slide it into place on the plastic piece under the gear.
Next, I drop the screw into the focuser screwhole and through the custom bracket and I tighten it very tightly with a nut on the bottom.
Now, the next time I’m out, I just plug in the focuser’s cord into the auxiliary port on my telescope and I can control it with my Autostar 497 hand controller or if I’m hooked up to my laptop, with my software.
Having the electric focuser allows me much more precision in focusing and makes it easy for me to focus without touching the telescope. It now means the knob on the other side is nearly useless (though I can look at it and see if it’s turning) because you can’t turn the shaft except with the motor now. Of course, I’m always plugged in with this scope, so it’s not a big loss and if it ever broke I could just unattach it and use it manually again. I’m planning on someday in the future replacing the focuser with a much nicer one (the stock SN-8 focuser is not very good), but until that day I’ve got a much better system. Over the past year as I’ve used this, it’s really been fantastic and I’ve become almost addicted to electric focus. It’ll be hard to do without if a future focuser doesn’t have that option.
July 20, 2009
Well, I did some work on my Peltier cooler for my camera and it worked pretty well with one caveat. I added a switch for the fan so I could turn it on and off as desired and I added a rheostat to the cooler so I could set the cooling level. Unfortunately, I don’t think the rheostat I was using is capable of handling the amperage I’m putting through it. It’s okay if I have it at 0 or 100%, but anywhere in between it heats up a lot to the point where I smell something burning. That said, it worked perfectly up until then – I was able to set it at 40% and it maintained the temperature above the dew point, but just barely. What I wound up doing is just setting it to 100% and turning the whole thing on and off to keep the temperature at the right level. I’ll look for a more capable rheostat later this week, if indeed that’s the problem. Any suggestions from electrical folks out there would be appreciated. I’m pretty new at this wiring thing.
Anyway, it’s a nice night and so I took a long picture of the Greate Globular Cluster in Hercules and now I’m imaging some other stuff. Unfortunately, I probably will not stay up long enough to image Jupiter which is too bad because it seems that there is a dark scar found by a regular cloudynights poster that seems to be an impact of some sort. Unfortunately, I’d need to stay up until like 3 or 4 am to image it.
July 19, 2009
I have been working to attach a Peltier cooler to my DSI camera in order to cool it down when taking images, allowing it to be more sensitive. Tonight was the first real chance I’ve had to test it out.
I set everything up then started imaging M57 – the Ring Nebula. When I started taking images, the camera read 20°C, after turning on the cooler, it started dropping and in 10 minutes had dropped to 7°C. There was a lot less noise in the frames at 7°C than at 20. The image above is the result.
I next turned the scope toward M27, the Dumbell Nebula, which was nearby. I started capturing it, but it looked wrong. After a minute or two, I figured out what was wrong – the camera had dew on it. I had lowered the temperature too much. Here was the result:
You can see that the nebula doesn’t have a lot of definition and the brighter stars have foggy halos.
I need to figure out how to keep the camera cold, but not too cold.
March 5, 2009
Because of the clouds this evening, I haven’t gotten the scope out, but before it got dark I took images for 360° while standing in my driveway where I put my scope. I then used Autostitch software to create a panorama from those images. After a bit of image work, making the sky transparent, I tried using the panorama as a landscape in my Stellarium planetarium software. WOW! It does a great job of letting me see what things will look like now. A big problem for me is my house blocks much of the eastern view from my driveway where I observe. Now I can, with reasonable accuracy, determine when things will rise above my roof.
January 17, 2009
I’ve been interested in doing wide-field astrophotography for a while, so today, I made an adapter that will allow me to mount a camera on my old equitorial mount that came with my first telescope. This way, I can take really long exposures that have a huge field of view. This is a great way to get shots of the Milky Way, for example. It looks like it’ll probably be cloudy tonight, but as soon as I’ve got some good weather, I’ll get some images. Another good thing about this is that setup will only take a couple minutes and so it’s something I’ll be able to do even if I only have a couple minutes of viewing time.
August 7, 2008
Tonight’s sunset was really nice, but was not very encouraging for stargazing this evening. I thought it would be a good idea to work on a project that I’ve been working on sort of on and off for a couple weeks. I purchased a Meade 1244 Electric Focuser which is not designed to work with my telescope (there isn’t one for my telescope). I knew I could make it work with the right bracket and I wound up fabricating one this evening out of supplies I’d bought a while back.
Here’s the bracket:
It wound up much simpler than I had feared – it was actually a lot harder to make the shaft extender, but I was able to do that using a brass rod and my tap set. It worked great and here’s the final assembly:
It seemed to work well, but the proof would need to come while stargazing so I peeked my head out and while still somewhat cloudy, the stars and Moon were mostly visible. I would try it out tonight!
Unfortunately, by the time I got set up, the Moon was behind some clouds, so I couldn’t really focus very well:
It worked okay, but I’ll need to try something else.
July 14, 2008
I’d been meaning to put up pictures of the damage that my telescopes incurred when they fell of my mount a week or so ago. Here’s the focuser of the refractor which snapped. I believe it took the brunt of the fall and sacrificed itself for my bigger scope.
This was the most serious damage to the main scope – a dent on the mirror cell. The mirror itself was fine.
The finder scope screw that was sheared off will be easy to replace.
Overall, it could have been much, much worse and I’m thankful I’m not having to buy a new telescope.
July 3, 2008
Tonight, while slewing to Jupiter, after observing for an hour or two, my scope suddenly fell off the mount. I don’t know if I had it insufficiently locked or if I just failed to tighten the secondary screw, but it fell right off the mount onto the driveway. It hit first on the bottom (mirror) side, slightly denting the aluminum housing, but not the tube. It then bounced off of the eyepiece (my 26mm Meade Super Plossl), which was undamaged and then finally hit the focuser tube of my cheap 70mm scope, breaking that. During the time it bounced on the concrete, which seemed like forever and I couldn’t get there in time, I kept waiting to hear the sound of breaking glass, but I never did. When I examined the scope, other than the dent and the broken cheapo ($25) scope, everything’s pretty okay. The eyepiece is fine and I went ahead and reattached everything to test it out. It appears fine. I think the shaking unaligned the finder scope just a bit, but that’s easily fixed. The focuser seems to be working properly and the telescope seems to be working as it should.
Right now, I’m imaging, to kind of test it out and everything seems to be going fine. The feeling of dread that I had deep down in my chest was awful, but it all turned out about as well as it could. While I’ll need to fix the cheapo scope (or replace it), that’s really the extent of the damage. I’m really, really glad my cameras weren’t attached at the time or they would have borne what the eyepiece did. While I love that eyepiece, it’s one that would be easy and inexpensive to replace, unlike the cameras…