Does anyone use a Sky Commander XP4?

Oz (Chris) · #1 13-11-2011, 12:23 AM

Hi I'm new to IceInSpace, so I may have already missed a discussion about the Sky Commander XP4, but I was wondering if anybody has one attached to a Dob, and if so, does it work? I've not been able to get mine to anything more than frustrate me! It all seems set up right but it gets me nowhere near the objects I look for - I mean not even close! I line it up using alpha Aquila and alpha Andromeda and ask it to locate M74 in Pisces (i.e just beside Andromeda) and the thing tells me its 40 degrees below the horizon! I just don't see how it could be so wrong ...

Barrykgerdes · #2 13-11-2011, 07:48 AM

Hi Chris
I don't know the Sky commander but from its specifications it appears to be pretty much the same as any other digital setting circles.

The first thing to check is that the encoders are corrrectly attached to the AZM and ALT axes so that the rotation information gets to the little computer.

The next thing to do is ensure that your location is entered in the computer correctly. This information will normally be stored permanently. Turn the device off.

Set your telescope with the OTA horizontal and pointing north. This will just set the encoders at a convenient starting point. Turn the device on and enter the date and time (with correct time offset).

The alignment can now be started. You need to pick two bright stars that are easily identified and as far apart as possible. The two you have selected would not be easy to identify so I suspect you have not identified them correctly. The two stars I like to use in the summer months are Betelguese and Acrux. Both these are quite distinctive. The first is very red and bright and the second will show as a double through your eyepiece.

When your two stars are centered and accepted the device should tell you whether the alignment was satisfactory. You should now be able to locate those elusive objects.

Barry

casstony · #3 13-11-2011, 12:07 PM

Hi Chris, I use the Sky Commander on two different alt/az mounts and had similar confusion to you when I first got it. The problem turned out to be incorrect setting of the encoder sense.

To check the altitude/dec encoder: after alignment point the telescope horizontal and due south, then slowly move straight up through 10 or 20 degrees. The numbers should increase - if they don't you need to change the encoder sense as per the manual. Note that once you pass the south celestial pole (-90 degrees) the numbers will start to decrease again.

To check the RA encoder: after alignment point the scope horizontal and due south. Slowly move the scope towards the east. The numbers should decrease - if they don't you need to change the encoder sense as per the manual. Note that the numbers will increase if the scope is pointed above the south celestial pole, moving from west to east.

I hope that helps. This is all assuming the Sky Comm has been set up according to the manual. Unless you want to find planets the alignment procedure only requires you to point at two alignment stars - no date or time needs to be entered and the scope doesn't need to be pointing anywhere particular prior to alignment.

Julie1 (Julie) · #4 17-11-2011, 01:30 PM

I have been having problems as well with my new SkyCommander XP4. The altitude seems to be OK but the azimuth doesn't seem to work. Sometimes it is way off and at other times it doesn't seem to change readings. I will try the setup suggested by Barry and see how it goes. It has been very frustrating so far as I bought the unit to make using my dob a lot easier.

casstony · #5 17-11-2011, 02:04 PM

There is a Sky Commander Yahoo Group that might be of use.
http://tech.groups.yahoo.com/group/SkyCommander/

Julie1 (Julie) · #6 17-11-2011, 11:36 PM

Those instructions were spot on. Thanks guys. It's a pity the instruction booklet doesn't mention that in the setup! Even with partly overcast skies and being in an urban situation, I was able to locate a cluster of galaxies in Aries. I'm really hanging out now for some clear skies. Chris, just follow those instructions and you won't go wrong.

casstony · #7 18-11-2011, 09:58 AM

Good to hear you got it sorted Julie. What ended up being the problem?

Julie1 (Julie) · #8 18-11-2011, 10:42 PM

Hi Tony, the problem seemed to be fine tuning the setup. As per usual, the instructions are not detailed enough. Nowhere in the booklet did it say about levelling the scope and pointing south to check the encoder direction.It's about time that manufactures in the northern hemisphere realise that the sale of their products is not limited to one part of the world! I should have realised this but not to worry, everything seems fine now. Thanks again.