Power Supply Mod

I've been wanting to replace the battery clip style connector on my ETX's 9v supply. Today I picked up a type N bayonet style jack from Radio Shack on Trenton and 10th. Two others on 83X and N Conway were unable to help. Radio Shack seems to be dropping their parts merchandise gradually. Type N is 5.5mm OD and 2.1mm ID. They didn't have the matching plug in stock so I'll either have to use something from the junkbox or wait until the weekend. In the meantime, I can install the jack on the ETX and either switch to the portable power station or keep using the wall wart supply. Tomorrow is partly clear, so maybe I'll get a quick peek at the moon or the sun then.

Train Drives

Rainy today so it was a good day to Calibrate and Train my ETX70 drives. Calibrate is simple and automatic and needs to be done when power supply changes are made. Training was done with my 10x eyepiece and a slow slew rate. I need to redo this when I can train using Polaris. My new focus extender worked well, for awhile. As I was finishing up it broke! I re-glued the knob and will see if that fixes it. The ETX site says that training is indicated by 'rubberbanding' or when the drives slew away from a target that has been manually positioned. Mine does this a lot at higher power. Hopefully this will cure the problem.

Park telescope checkout

I spent about 4 hours today checking out three of the Park's telescopes: Celestron 5", Orion 3", and Meade 4". The Celestron continues to look good. The optics are in pretty good collimation. The targets were all in alignment although it could be a bit better. The tripod is a little bit wobbly but otherwise seems serviceable. It is missing a locking bold on one leg. This tripod is similar to the one's on the Orions and one of those bolds may work temporarily. I plugged the drive into my 12v portable power station (Chicago Electric from Harbor Freight, $90) and everything fired up. Movement is smooth and handbox buttons all work fine. I tried pointing at a distant tree and verified that the 'save land object' and 'goto land object' functions work. If the scope is in the near vertical position there is some interference between the OTA and the tripod. This may be normal but needs to be checked out and if normal, watch out for it. There doesn't appear to be any protection and the gears might be stripped. The view through either 25mm or 10mm eyepieces seems good and I could tell no difference between the available ep's and my Plöessls. Some of the eyepieces are marked KE and others are Orion Explorer II. They all look similar. Tristan Schwartz at Cloudy Nights gives them high marks. They are basically either Kellners (25mm) or Plöessls (10mm). The Celestron's red dot finder needs a 3v battery.

The Orion 3" Spaceprobe needed a bit of tightening and it is now steady as a rock. The tripod seems sturdy enough although I did not extend the legs. The optics were in perfect collimation. The red dot finder also needs a battery. There are three more boxes in the storage room that may also be Orion 3" scopes. These also need to be taken down and checked for missing/damaged parts.

The Meade 4" tripod is pretty much unusable when the legs are fully extended. They flex quite a bit. The azimuth bearing is very wobbly and the altitude bearing a bit so. The most serious problem is that there are no eyepieces. The focuser is a 2" barrel but it was fitted with a .965" adapter. There is a 2" bushing but no threaded ring to hold it on. It needs a 1.25" adapter before the existing eyepieces can be used. I was able to install the second motor. The power supply is 12v but my bayonet connector would not fit so I was not able to check out the drive operation. The Autostar handbox appears to be unused as the protective cover on the screen was still in place!

Here are the magnification firgures for the three scopes. The 3" is a 700mm FL, the 4" is 910, and the 5" is 650mm. Magnification available for the 3" is: 700/25 = 28x, and 700/10=70x. With a 2x shorty barlow this gives magnifications of: 28x, 56x, 70x, and 140x.
Magnification for the 5" is:
650/25 = 26x, and 650/10 = 65x. With a 2x barlow, that gives 26x, 52x, 65x, and 130x.
If the 4" is ever usable, it's 910mm focal length will result in magnifications of: 910/25 = 36.4x, 9210/10 = 91x or 36.4x, 72.8x, 91x, and 182x.
The next step is to try star testing the optics. It'll be interesting to see what sort of detail can be seen on Jupiter and how well the two scopes can split close doubles.

First day as Park Astronomer

Today was my first day on the job as Park Astronomer for Bentsen Palm State Park. First order of business was to find my 'office' and do some inventory on the park's collection of astro-scopes. They have quite a collection of some really nice optics used for their birding outreach but not so much for astronomy outreach. I went in with the expectation that I would either be driven to the depths of despair with junk or completely elated with some fine optics. Actuality was something in between. Definitely not junk though. There are a number of Orion Spaceprobe 3 AltAz newtonians, and a couple of goto newts. All are altaz tripod mounts so alignment will be straightforward and the little Spaceprobes have red dot finders at least. One goto is a Celestron Starseeker and the other is a Meade Telestar DS-114. The Orion mounts are lightweight wiggly-looking altaz tripods. It might be better to try to mount these on a dobsonian base of some sort, either commercial or homemade. All have 10 and 25mm eyepieces. The goto's appear to both be 12v AA driven. One battery box is slightly damaged. One eyepiece appears to be missing. All equipment is in the Audio Visual room which stays locked. I am to contact Javier (off friday and saturdays), Roy, or Melissa to gain access. Observing can be done in the office courtyards (dark with power), or the middle loop in the park (power available near restrooms), or out in the yard. Green laser pointers abound as do binoculars and 50mm spotting scopes.
The park hosts a 'night hike' on Wednesday and Saturdays as well as monthly special programs for volunteers. The Saturday night hike would be a good place to start some sort of outreach program. An astronomy program for volunteers would also be good.
First order of business is to complete checkout of the telescopes and familiarize myself with their operation. As a volunteer, this should be fun. If nothing else, I can work at my own pace!
Research results: The DS-114 gets uniformly bad reviews. The Spaceprobe 3 gets good reviews as a beginner scope, but this is for their SP3 with equatorial mount.
The Celestron is basically a NexStar GT. It remains to be seen about details like which handbox is attached but the site www.nexstarsite.com has a wealth of material on it, similar to Weasner's ETX site. I'm hopeful about this one as Orion sells it and it is essentially a current product with some support. It has a 1.25" focuser and an Orion EZFinder.

A Look at Cassiopeia

It was clear, not too windy, and not too cool tonight (64°F) so I thought I'd set up the ETX-70 in the backyard observatory. I picked weeds and swept the dirt off the bricks, set up my rickety pedestal, leveled it, set up the furniture, and set down to business. I decided to try for the double Eta Cas which was featured in Oct S&T. Cassiopeia is in a nice position for my backyard right now. I thought for awhile that my neighbor's new satellite dish was going to block Polaris and ruin my ability to find north but Polaris was well above the obstacle. I got lined up ok and used Shedir as my alignment star. A little hunting around and checking star fields convinced me I had the right bright light in my eyepiece so I centered up on Eta Cas. Next I put in my 10mm ep and recentered. Still just one star, so I added the 2x barlow. It takes quite a bit of turning of the focus knob to bring things into focus. I need to get a focus extender or electric focuser! I got it all working together which gives me about 70x ((350/10)*2) and thought I had Eta split into a red and blue pair but decided later that it was just an artifact of my eyeball's fancy multifocal lenses. Any bright star looked like a double! I may have to resign myself to not being able to observe doubles very well, other than really wide pairs, at least with the ETX. Things are a bit better with my dob. While I had 70x installed, I decided to slew over to Jupiter and almost gave up trying to find it. I discovered that I can insert my 25mm ep, get the fuzzy blob image of Jupiter centered, then put the 70x assembly back in the tube and voila! A nice big, clear Jupiter! Both storm bands were crystal clear and all four moons (3 on left, one on right) were plainly visible. I played around a bit more with Cassiopeia awhile before it got too cool and I went in about 8:15. All in all, a nice night without too much frustration.

Finally Jupiter

Jupiter has been calling my name, begging to be observed, for the past several nights. Tonight was cool and clear with NO WIND (amazing), so I decided to dust off my ETX-70 and setup in the front of the house, street lights and all. At least I had plenty of light to get things level and check out everything. When I finally turned on the power, the comedy of errors began. I had made a mental note to myself to be sure and change the Site setting from Rolla to GGG. Of course I forgot. I also forgot to snug up all the leveling bolts on my pedestal contraption, soooo... after guessing which way was north, I aligned on my favorite fall star: Capella. The scope was clearly way off, mainly too low. Did I say that I also set the time wrong? After noticing that the base was wobbling, I snugged up the rest of the bolts and made sure things were level. A couple more tries and I finally remembered to set the time and Site correctly. Finally got Capella with a minimum of searching. Aligned more or less, I next slewed to Jupiter, burning bright above the garage. A bit more searching and I had it in the crosshairs too. I spent probably the better part of the next hour admiring the view through various filters, my 10mm and 2x barlow. All four moons were clearly visible in the 10mm, kind of hard to make out with the 26mm. I was able to see two storm bands pretty clearly.
Next I tried for Uranus. No luck, it was behind a palm tree. On to Neptune. I thought I had it but the star field wasn't quite right. I tried lining up on Delta Cap but never was able to snag Neptune for certain. It may also be a bit dim at almost mag 8. Uranus should be ok if it comes out from behind the palm tree (or I move the scope). All in all it wasn't too bad for a first night out. Oh, and I also banged away and cursed the speed button before I realized it wasn't the Enter key! How soon we forget.
Now I'm trying to decide if it is worth hauling this thing down to the park when and if I ever get to do an astronomy outreach program there. We'll see.

Back in The Valley

We've been back in El Valle for a couple of weeks now and I have yet to haul out the little scope. I have been enjoying the near horizon views in the west at sundown and managed to snag Mercury several times, shining through the murk below Venus. Jupiter is nice in the east just after sundown. Need to keep better track of the ISS. Here is a photo I took at Sandcastle Days on South Padre Island right after we got here in October. We're headed back tomorrow for the SPIKE monthly kite fly.