33 replies to this topic

[Wingman62]

Thanks Jim and everyone.

 

I may still buy Skytools3 it looks like a pretty cool program.

[han.k]

Freeware planetarium program HNSKY can guide a telescope every second to the calculated comet position. This allows long time exposures where the comet is sharp and stars will trail. Below an example of a single 600 second exposure using "math guiding". Mount was a HEQ5. An accurate polar alignment of the mount is required.

 

The procedure is simple. Click on the planetary object, use the right mouse button and select TELESCOPE and then select FOLLOW 2P/ENCKE or how the object is called. You have to set the interval to 1 second in the setting menu. This feature was initially designed for following occultations but by setting the interval to 0 this is interpreted as one second.

 

This is a standalone solution. A better way as mentioned before is to guide on a nearby star and calculate the offset required for the following comet. This can be done in PHD & CdC but is more tricky.

 

Han

 

Feature is described in the HNSKY help file:

http://www.hnsky.org...y.htm#telescope

webpage: http://www.hnsky.org/software.htm

 

 

 

Edited by han59, 19 February 2017 - 05:24 AM.

[rmollise]

I have unsuccessfully tried several times to use Stellarium to find and track comets.  Tried to find Catalina 2013 last year and Honda 45P last week.  In another post I heard from other members that Stellarium's data for 45P was not as accurate as it could/should be.  From my own efforts I also figured out that Stellarium was not attempting to actually track the comet.  It was merely tracking the area of sky where it thought the comet was at the moment you told it to slew the scope to 45P.  Since I was observing on the 11th when the comet was its closest to Earth, I could actually watch the comet leave the crosshairs on the computer screen.

 

So I am wondering if there is a better piece of software I should be using that A) Actually tracks comets and B) Actually knows with a high degree of accuracy where the comet is on any given night.

 

SkyTools seems like a possibility. Any SkyTool users out there that have used it to find and track comets?

I've found Stellarium to work just fine. Make sure you have the latest version.

[Wingman62]

Thanks han59.

 

My viewing buddy and I are going to try to get this nailed down.  I'll let yall know what we find out.

[rmollise]

I used Stellarium to center 45P for imaging the other night. Worked like a charm.

[Stargazer3236]

I use https://theskylive.com/comets for my ephemerides on Comet positions. I can enter the coordinates into my Hand controller for either my iOptron ZEQ25 mount or my Celestron Nexstar mount. Once I input the correct coordinates, the scope has no problem of finding and tracking the comet too. Also, Sky Safari 5 Plus also has a great locating option in its database that I can gather the coordinates of and enter them into the HC or when hooked up wirelessly to control the mount, I have no problems finding and tracking the comets either.

 

I would use the Skylive dot com website for updates, as they are updated routinely and are quite accurate.

[Tonk]

Now I'm curious how those who do comet AP can get their mounts to track the comets and get such good detail, all while leaving star trails.

Answer is you don't track the comet - you do it all in image processing using double stacking techniques (stack aligned on stars, stack aligned on comet) - click thumbnails below to go to tutorials

 

Do this to get this

Do this to get this

Some more advanced stuff
 

If you track on the comet you will always end up with trailed stars like this

- you cant undo the trailing so re-shoot the field once the comet has gone for the stars and use an extraction method for the comet


Here are some more examples of "star freeze" processing

- -

 

Edited by Tonk, 05 April 2017 - 11:34 AM.

[StargazerLuigi]

I've only done it successfully once, but, I had my guide camera guide on the comet's nucleus. I inserted a pause in between comet shots shot that the trailed stars would be rejected when the stack was integrated.

 

Then, get a picture of the field after the comet has gone.

 

Combine, like Tonk, above, has outlined.

 

Astro-Physics mounts when controlled by APCC can be set to guide a custom rates. Before APCC there was a way to 'teach' the mount how to tracking using PulseGuide, if I'm remembering correctly. Essentially you'd guide on the the comet and the program observes your RA and Dec rates and uses those instead of sidereal.

[Edward E]

The PHD2 Guiding software seems very slick just from reading the info from the web page.  Nice to know that there is software that will let you do this.  Thanks!