29 December 2015

A Deep-Sky Planer user asked me to create observing plans for objects in the Small Magellanic Cloud (SMC). The data came from 5 catalogs revised by Mati Morel of New South Wales, Australia. I contacted Mr. Morel about the project, and he kindly gave permission for me to use his work. He also sent me the latest updates to his data.

Small Magellanic Cloud. Credit: NASA/CXC/JPL-Caltech/STScI
The data in this series of plans are contained in 5 lists compiled from examining the Hodge & Wright atlas of the SMC (1977). Mr. Morel examined the atlas and consulted various sources for position, magnitude and size information for each object. He also included comments on many objects. I have used the latest published data from SIMBAD for position, magnitude and size. There appears to be little difference between the two sets of data, except that magnitude information is somewhat different. There is photometric data available for most objects in multiple bands. The band used for the magnitude data for each object in the plans is indicated. Magnitude data in the V band is preferred where available. I believe this is more useful to visual observers.

Together, the 5 plans contain 405 objects. Some entries are duplicated among the catalogs, but together these represent a thorough coverage of nebulae and clusters in the Small Magellanic Cloud.

The plans in the Deep-Sky Planner Plan Library are named:
  • SMC Henize nebulae
  • SMC Hodge Wright clusters
  • SMC Kron clusters
  • SMC Lindsay clusters
  • SMC Westerlund Glaspey clusters

  1. Morel's comments are maintained in the User text column. These are essential to his work.
  2. Object types in DSP are not as narrowly defined as those in SIMBAD. For example, 'Open Cluster' is assigned in Deep-Sky Planner to object types 'cluster of stars', 'star association and the like in SIMBAD.
  3. Lindsay's paper is crucial to understanding the clusters in the SMC. You can read it here.
  4. Lindsay 106 and 109 are mislabeled on the Hodge & Wright (1977) atlas of the SMC

10 December 2015

Adventures with Sky Commander

I have used a Sky Commander digital setting circle computer with my telescopes since 1991. I can thank Tom Clark from Tectron Telescopes for turning me on to this wonderful gadget. I wouldn't be without it.

My first Sky Commander started out on a 20" Dob and later moved to a 14.5" Dob. I also added encoders to a 8" Dob so that I could use the Sky Commander with it. I have been running my Sky Commander on both the 14.5" and the 8" for years.

I recently got a new Sky Commander XP4 to use on the 14.5" so that I can permanently assign the older one to the 8". The configuration is a little different on the two scopes, so having one Sky Commander for each scope is helpful.

Old and new Sky Commanders

A feature was added to Deep-Sky Planner 6 that allowed users to upload an observing plan to the Sky Commander in its special objects list (entries 0-58). I have used this feature to upload coordinates for comets, asteroids and deep-sky objects that weren't in the Sky Commander database.

While testing Deep-Sky Planner with the new Sky Commander, I found that I still had to upload plans when the Sky Commander was at the Set Date prompt. That requirement never seemed right to me because I didn't see it documented anywhere.

I contacted Sky Engineering about this and we found that a firmware change would cure the problem. After some back and forth and some testing, a new firmware version emerged. I flashed the new firmware into the XP4 and the problem was solved!

Going forward, Deep-Sky Planner users with a Sky Commander having firmware prior to version 5.03 SP02 will need to upload plans when Sky Commander is at the Set Date prompt. Users that are able to update the firmware to version 5.03 SP02 or later should be able to upload plans to Sky Commander when it is at the Set Date prompt or in its normal operating mode. This is an added convenience that will make using Sky Commander with Deep-Sky Planner a little smoother.

I'd like to thank Victor McKeighan at Sky Engineering for his kind help in resolving this issue.