Jan 272016

Since I am now waiting for the reprogrammed mount control panel to return I have some time to catch up with some archived imagery.

Once thought to be a supernova remnant, this nebula is now known to be an old planetary nebula. It was discovered by renowned astronomer George Abell in 1955. This is one of the first objects in the Sharpless catalog that I have imaged.

Using Palomar Sky Survey plates as source material, US Naval Observatory astronomer Stewart Sharpless published two catalogs of H II regions. The catalogs also contain some planetary nebulae and supernova remnants. This nebula is one of those and the 274th item in his second catalog.

Medusa Nebula (SH 2-274) [C:60x30s]

Medusa Nebula (SH 2-274) [C:60x30s]

Chart generated with Cartes du Ciel

Chart generated with Cartes du Ciel

The nebula is located in the constellation Gemini on the border with Canis Minor. It is estimated to be about 1500 light years distant. Deeper exposures than this show the nebula to have a braided appearance hence the Greek mythology Medusa name reference. The nebula is also cataloged as PK 205+14.1 in the catalogue of galactic planetary nebulae published by Czech astronomers Luboš Perek and Luboš Kohoutek.

 Posted by at 12:27
Jan 272016

I am still fighting the somewhat troublesome new mount. When the mount is commanded to slew to a target it gets close but does not center it, even in a wide FOV eyepiece. Most importantly, the mount does not track precisely. Even in a short 30 second exposure the stars streak significantly. Finally, the mount also does not park all the way. It also gets close but does not reach the designed position.

After several fruitless iterations of user group questions and answers, the group moderator had me call the factory and talk with the technicians. A short troubleshooting session over the phone led the technician to a quick diagnosis. His suspicion is the control panel thinks it is on a different model mount. He classified it as a ‘personality’ problem. It is technically possible to update the control panel’s internal settings over the internet, but the “regular crew chief” is out sick, so the control panel is now in the hands of the post office.

Meanwhile, I have had plenty of time (and adequate weather) to resume work on the floor panel reconfiguration. Now finished, it is obvious which panels are new due to the new carpet, but they should weather fairly quickly and blend in once summer arrives and drives the temperature up in the dome room. But, most importantly, I can now pull up the floor and work on the wiring and plumbing without having to disconnect anything.

 Posted by at 11:13
Jan 212016

This image shows the first bright sky meteor that the Sky Sentinel meteor camera detected. I normally disable the camera during daylight hours. This cuts down on the camera detecting birds, insects and aircraft. This morning (20 Jan), just before detection was disabled, the camera recorded this very bright meteor in the dawning sky.


 Posted by at 01:31
Jan 112016

The floor tasks have been put on hold for more conducive weather conditions and to be ready for the occultation on the 12th.

The original configuration of the control wiring and plumbing through the floor has been restored. However, the wiring configuration at the mount has changed drastically. The AP1600 allows the cabling to the focusers and cameras to be routed through the mount. I’ve rolled the dice and also routed the cooling hoses through it as well. This routing scheme significantly reduces the chance of wiring or hoses snagging on something. The size of the Losmandy mount prevented through the mount cabling so it was all external.

One of the challenges of a German equatorial mount has always been cable routing. Over time I had come up with a fairly good configuration, but there were certain positions in the sky that could result in a temporary snag. These weren’t critical enough to damage equipment; they would be just cause enough drag to upset the guiding and ruin an exposure. The snag would then release and most of the time the mount guiding would recover. Once in a while I would have to go into the dome room and adjust the way the cables were hanging. Hopefully, that tasking is over.

So, here is progress made in the list of upgrade tasks:

  • The scope has been balanced. The mount is fairly stiff and with the current weight load nowhere near the advertised limit, balancing it was not as finicky as the Losmandy. I still have another counterweight in the box for the 12.5″ scope. It may not be enough.
  • The new ASCOM driver has been installed and is operational. Since the polar alignment software that came with the mount required it, installing it was moved up in the list. So far, all the supporting software packages seem to be playing well with the new scope control system.
  • I started the polar alignment process on the 6th of Jan. and was able to get most of the way through it before clouds moved in. Finished initial alignment on the 7th.
  • Characterizing any periodic error has not been accomplished yet. All recommendations that I have found said to perform the mount alignment first.
  • In order to accurately position the slit in the dome, the dome controller needs to know where the mount RA axis of rotation and Dec axis of rotation intersect. If that intersection is not at the center of the dome, the differences need to measured and entered into the mount driver. Obviously the new mount is at least 18″ higher in the dome with the pier spacer. The intersection of the mount RA and Dec axes are also not the same as the G-11. So, I had to restring the dome and measure the new offsets. That has been done.

The AP1600 has 4 predefined parking orientations. I always parked the G-11 in the traditional equatorial position that everyone thinks of; telescope pointed at the north celestial pole with the counterweight bar down. However, that position is not the preferred position for this mount. Park position #4 has the telescope parallel to the ground facing south and the counterweight bar parallel to the ground facing west. It is definitely unconventional looking but has a totally unanticipated benefit. With both axis parallel to the ground and with the addition of the 18″ pier spacer, the lowest point of any piece of equipment is 6’2″ above the floor. I can now walk around the dome room without fear of bumping the mount and having to re-do a mount alignment.

UPDATE: There is significant star streaking during a 30 sec exposure. I have spent the last two days trying different techniques to eliminate the streaking. So far, no joy.

 Posted by at 14:44
Jan 022016

The observatory upgrade proceeds, but the outside temperature has delayed cutting new floor panels. The current plan is to try again over the next couple of days. If the conditions don’t improve I will restore the previous floor/wiring configuration to bring the PTO back online as soon as possible and watch for the next favorable opportunity to resume the floor task. I am anxious to observe the shadow of minor planet (1424) Sundmania as it passes across the panhandle on the 12th of January.

In the meantime I am processing a backlog of imagery.

This image was taken on the 14th of December. NGC 2266 is a compact open cluster discovered by William Herschel in 1785 in the constellation of Gemini. It is relatively old for an open cluster and has an estimated age of 1 billion years. The cluster’s distance has been estimated as 2.6 kpc (8485 ly).

NGC 2266 [C:58x30s]

NGC 2266 [C:58x30s]

Chart generated with Cartes du Ciel

Chart generated with Cartes du Ciel

 Posted by at 15:01