Can't set scope to desired RA/DEC

[Markinaboat]

Hi,

 

Firstly, I hope this isn't the wrong place to ask.

Was out with my Orion XT8i on Weds night and was determined to find C/2017 T2 Panstaars. (and then C/2019 Atlas thereafter). My scope has Orion's push-to system which I've used successfully on several occasions. This time however, I got the RA & DEC from Stellarium for the comet and set the hand controller to RA/DEC mode. If you're not familiar with this, once the setup is aligned, it displays the RA & DEC (supposedly) to wherever it is pointed. But, I found it impossible to get both coordinates (RA & DEC) displayed simultaneously as any adjustment to one through the other out. I must have been playing with this for a good hour but to no avail.

 

Can anyone shed any light on this? Maybe there's something up with the controller. I should add that the encoders work correctly without spinning and the push-to cordinates work well when searching the database.

 

And after several hours, I still did not find any of the three comets in CAM. I scanned the skies meticulously with my ES 30mm and Nagler 22mm ep's to no avail.

 

Thanks in advance for taking an interest in this post and hope everyone is safe and well if not entirely sane! 🙂

[Oldfort]

I'm not familiar with the Orion push to system, so this is guesswork.

C/2017 T2 is relatively close to the North Celestial pole, so  unless you approach an object along a line of right ascension (ie heading directly towards or away from Polaris), both RA and dec will move all over the place.  One way around this would be if there is an alt/az mode,  on the mount and use that.

 

Conversely, when using an alt-az scope, pointing near the zenith is a challenge.

Also, the nominal magnitudes shown for comets are a bit misleading, because the light is spread over a large area (a bit like the larger galaxies) and unless you have a really dark site, they can be difficult if not impossible to find.

[Markinaboat]

On 27/04/2020 at 18:45, Oldfort said:

I'm not familiar with the Orion push to system, so this is guesswork.

C/2017 T2 is relatively close to the North Celestial pole, so  unless you approach an object along a line of right ascension (ie heading directly towards or away from Polaris), both RA and dec will move all over the place.  One way around this would be if there is an alt/az mode,  on the mount and use that.

 

Conversely, when using an alt-az scope, pointing near the zenith is a challenge.

Also, the nominal magnitudes shown for comets are a bit misleading, because the light is spread over a large area (a bit like the larger galaxies) and unless you have a really dark site, they can be difficult if not impossible to find.

Hi and thanks for your reply. Makes sense re RA/DEC. I did lookup the ALT/AZ  coordinates but when I set the scope to them, it was in a completely different part of the sky. The scope was well aligned so nothing to do with that.

[Peter Drew]

Is there a difference between the way Intelliscope and Stellarium input their coordinates?

[Markinaboat]

40 minutes ago, Peter Drew said:

Is there a difference between the way Intelliscope and Stellarium input their coordinates?

I wouldn't have a clue Peter.  But I would've thought ALT/AZ coordinates were pretty straightforward and at least put the scope within say a 30 degree window.

[Peter Drew]

I was thinking along similar lines to the problems caused by American date format, longitude and latitude order of insertion etc.  I have a 8" Intelliscope but have not had similar problems in the past.   I have also only used the handset data.  The other potential problem area that springs to mind is battery power, the scourge of electronic wizardry.        🙂

[Phil Fargaze]

I have an Orion XT10 with the push to system and I remember finding an object before by displaying the RA and DEC. It was a bit fiddley but wasn't too bad. As mentioned before I would think it will be difficult to do at high elevations. Normally if I wanted to find a comet I would input it`s RA and DEC as a `User-Defined Object` then it is a simple matter of just re calling the object and pushing the scope to it. 

[Markinaboat]

4 hours ago, Phil Fargaze said:

I have an Orion XT10 with the push to system and I remember finding an object before by displaying the RA and DEC. It was a bit fiddley but wasn't too bad. As mentioned before I would think it will be difficult to do at high elevations. Normally if I wanted to find a comet I would input it`s RA and DEC as a `User-Defined Object` then it is a simple matter of just re calling the object and pushing the scope to it. 

I've never needed to set RA/DEC before and wasn't aware that they could be input? Assumed (incorrectly) that the user defined object would have been set from where it was pointing. Will have a play with this although not sure how much 'comet' time is left other than C/2020 F8 (Swan).

[Phil Fargaze]

I guess your hand set is the same layout . I’ve attached a picture of mine.  When I press ‘user’ which is no 9 key, I get the screen as shown, for example. The bottom line is the RA and DEC which can be changed and is inputted by the number pads. The plus or minus of the dec value is changed by the up or down arrows. 

[Markinaboat]

43 minutes ago, Phil Fargaze said:

I guess your hand set is the same layout . I’ve attached a picture of mine.  When I press ‘user’ which is no 9 key, I get the screen as shown, for example. The bottom line is the RA and DEC which can be changed and is inputted by the number pads. The plus or minus of the dec value is changed by the up or down arrows. 

Thanks Phil, will give it a go at the next clear sky.