Sony DCR-TRV310

We originally purchased the Sony DCR-TRV310 for home video of family events. On a lark, I decided to point it into the eyepiece on night and was pleasantly surprised that I got reasonable images. It just so happened that I picked the moon as a target and it was only slight after the new moon. This was fortunate in that the entrance pupil of the camera is not well matched to the exit pupil of the 25 mm Plossl eyepiece I was using (25 mm with an f/6 scope gives an exit pupil of 4.2 mm, rather large for the video camera).

When the full image cannot enter the camera, you end up with a shadow from the secondary in your images. But, because I was imaging a very thin crescent moon, the shadow from the secondary fell in the dark part of the moon so I couldn't tell. And, because I couldn't tell, I went on to try imaging Jupiter and Saturn.

Sorry, I don't have any technical details on the Sony DCR-TRV310, but once I do, I'll try to post them here.

Using the DCR-TRV310

For the planets, the DCR-TRV310 can be used in the normal 29.97 frames-per-second mode. For deep-sky objects the camera's "candle-light" mode is preferable. In this mode, the camera increases the exposure time by approximately a factor of 8 to produce 1/4-second exposures. Output continues at the 29.97 fps rate, but each set of 8 frames is identical.

The DCR-TRV310 has three output methods, composite video, S-Video, and FireWire. The latter is preferred as it is completely digital and what was used. Capturing over the digital FireWire connection makes it easy to get rid of duplicate frames when using the candle-light camera setting; each set of 8 frames is completely identical and any tool which will allow you to compare files will tell you which ones are unique.

Because the DCR-TRV310 is a standalone camera, you don't need any computer at the site to do your video capture; just a supply of digital 8-mm tapes and your telescope.

QuickCam VC

I purchased a QuickCam VC from Computer Geeks when they had a batch on sale for about USD $15. I keep going back hoping to find another batch, but so far no luck. Up until this, I had been using a Sony DCR-TRV310, a digital videocamera.

The QuickCam VC is similar to the other QuickCams and some detail information on modifying the camer for astronomical imaging can be found at the AstroCam web site. There is one thing you should be aware of if you are going to follow the instructions there for disassembling the camera. The instructions clearly point out that there is a small hole covered by a sticker on ]the camera. In the case of my QuickCam VC, there was no sticker, so finding the hole was easy. What I didn't fully realize is that the clip you release by poking in the hole is only one of three holes. In fact, you can see this in the photograph the AstroCam site provides of the QuickCam after it has been opened.

Alas, I was too rough or careless when opening my QuickCam VC. After pulling the lens and IR filter off then remounting it, it would not work. I rather more carefully opened it the second time and found what appeared to be a small surface mount resister array that was barely hanging on the PC board. I packed up the whole thing and shipped it as a gift to Bob May (a member of QCUAIG) who has equipment to repair it; he identified it as a tiny op-amp (so much for my electronics knowledge).

Philips ToUCam

Although I wasn't able to find this at the sort of discount I received on the QuickCam VC, this camera is still worth the money. All comments by users on the QCUAIG mailing list indicate this is a great webcam for astronomical use. I purchased the camera in early April, and have only tried to use it once conneted to a small, 133 MHz Cyrix MediaGX computer running Windows 98. I have Vega, a program written by Colin Bownes, to capture images. Vega is oriented more toward some of the operations you want to do in amateur astronomy rather than general webcam stuff. However, I'm having some problems with MediaGX machine that make me think it and Windows don't really get along all that well (I mean, even worse than Windows normally is).

Since I originally purchased the camera, there have been a number of exciting developments with the Philips webcams. Steve Chambers has put together a number of hardware modifications (see here for the ToUCam Pro) to enable true long exposure photography. I have not made this modification (yet), but the results look very promising.

I obtained an adapter from Stephen Mogg which is a nicely machined piece of black plastic which prevents me from having to open up the camera and break something, as I did with my QuickCam VC.

The ToUCam Pro is no longer marketed in the USA, but is imported for microscopy work by PocketScope

I have a used laptop I received from a friend, but it is an older model with no USB port and no O/S installed. I installed Slackware Linux, but the Linux PCMCIA support doesn't include any USB cards. I've been completely unsuccessful at getting Windows 95/98 installed; something is flaky with the CDROM. Even with Slackware Linux, I was unable to install from the CDROM and had to do a network install.

60mm Refractor

About a year ago, someone on sci.astro.amateur mentioned that they had a couple of old 60 mm refractors in the closet. At the time, I was looking to buy one used and had been scanning garage sales and for sale ads without any luck. So I half-in-jest asked if you wanted to donate one. He sent me a private email and offered to send it for the only cost of shipping! Shipping was only $5, but I sent him a $20 check since I would have happily paid that for one at a garage sale.

The picture to the right is one of me with Matthew (age 3 years and 3 months) and Jonathan (age 11 months) "setting up" the telescope for a photography session of the 2001 Leonid meteor shower. You can see the telescope, the CG5 mount and a homemade box that functions as mounting "rings." The box design was used to give me a place to attach the ball heads I use for holding the cameras.

While functional, the box was heavy. I subsequently replaced the box with a more light-weight structure that also hold the cameras to either side of the telescope instead of mounting both on top. This improves the balance of the mount by keeping the weight closer to the equatorial head's axis. Here is a picture taken in June 2002 of the modified bracket just before being replaced with my Orion 127 mm Mak-Cas.

Subsequent to that "replacement" I returned the 60 mm Tasco to service as a guide scope and added two more ball mounts on either side of the finder, which I moved to attach to the OTA, so I can now shoot four cameras at once.

If you look closely, you'll notice the finder has a piece of transparent tape holding the eyepiece on. This finder is the original 5x30 finder from my Orion XT8 and the threads were damaged when I foolishly packed the scope into its carrying case with the finder still atached. The scope is held on the wooden base by a couple of webbing straps which are pulled very tight. This arrangement is not entirely satisfactory as the straps do loosen over time. Still, it works for now.

127 mm Orion Maksutov-Cassegrain

The 60 mm Tasco was great for getting me started on the road to photography with a good polar alignment. It's chief failing is its small aperture which leaves me with a small selection of alignment and guide stars. So I went in search of something better (i.e., bigger)

I had already found I really liked what I was hearing about Orion Telescope's (then new) Mak-Cas telescopes. The 127 mm version was getting some good reviews as being a good performer for the price. Since I was looking for a budget scope that could also serve for decent planetary views and hopefully some imaging of Mars during the 2003 approach, this looked like a good choice. The trick was that I didn't need the whole equatorial setup Orion was selling but if I chose to purchase the spotting scope version I would have to go buy some additional parts that would put the price right back at that of the equatorial version. Enter astromart and Astronomy Mall, great places to search for used astronomy equipment. On Astronomy Mall, I found an ad from Ken Dauzat for a used 127 mm Orion Mak-Cas with some nice mods included a 2-inch diagonal with a Crayford focuser for about the same price as Orion's equatorial version. I jumped at it, but someone had already contacted Ken. Fortunately for me, that deal fell through and the scope is now mine.

In the photo above, the Mak-Cas is shown with the camera mount bar and a (dead) Pentax A3000 on one of the ball mounts so you can better see how things are attached. Since I set this up solely for the purpose of taking a quick photo, I didn't bother to attach any counterweights.

A month after the purchase, I went to NEAF where I picked up an additional counterweight for the CG5 mount and an extra dovetail bracket. The biggest question was how to attache the cameras. Ideally, I should have a nice bracket that would attach them to the OTA, and some stock versions are available, but I wanted to be able to mount at least two cameras and buying one ring for every camera seemed excessive.

I started out by ordering a small steel bar from McMaster-Carr to replace the finder mount. The original that had come with the scope was a bit too short after I replaced the Losmandy GM-8 bracket with the CG-5 dovetail. I discovered that I made a small error; the original was aluminum which is a lot easier to cut through (especially by hand with a hacksaw) than steel. I took the remainder of the bar and drilled three holes, one in the center and one near each end. The center hole is used to secure the bar to the CG-5 dovetail, the ones on each end hold a camera ball-joint mount. The arrangement is a bit kludgey, but it does work. I used it that July and August to take a series of shots which mostly came out well.

The arrangement is far from ideal. The long moment arm of that steel bracket allows vibrations. However, I have only one shot that shows anything that might be due to vibrations and even there I have convinced myself that the real culprit was something else, possibly a loose bracket on that camera (I was shooting both cameras, and one only end shows the blurring). The bigger issue is something most Mak-Cas owners are quite familiar with: mirror flop when crossing the meridian. I should have known that, but just didn't think about it. So I have a few botched shots that were taken while crossing the meridian. The mirror flop for this scope is small, and I have no shots taken with a 50 mm lens that show it; only a couple with 135 mm and 200 mm lenses. Until I work out some scope mod to get a mirror lock in place, I've gone back to using the 60 mm Tasco as my guide scope.