Learning to use RA

[crovax]

Hi,

I am still a little confused with how I should use RA circle on my EQ2 mount. The screenshots are taken from Orion manual. Please check the first one (EQ2.jpg). There is a white arrow between R and A letters. As far as I understand I should point scope to e.g. Vega and then set its RA on the circle. So let's say I located this star and made this white arrow point to 18h 36m on the lower set of numbers (I am in Northern Hemisphere). But what's next? How do I compensate time? So let's say I left scope and returned in an hour. When I return the RA calibration will be lost, right? Is there any easy way to fix this?

On the second screenshot I attached you can see a metal pointer on the RA circle (right under thumbscrew). I don't have any idea what it is for so may be it is related to this whole thing. All I know is that this pointer moves with RA circle.

[philsail1]

Hello "crovax."

Rather than type a long explantion here, you may find it useful to take a look at the tutorial below on "setting up an EQ mount." This tutorial has come from STargazers Lounge "Primers and Tutorials" section. You can search this section for help with the basic setting up and understanding of how an Equatorial Mount operates.

From experience I know most people (including myself) don't use the setting circles on our scopes, to find things. The circles on most commercially bought scopes are too small to be of any real use). They might get you in the general direction of what you want to look at, but chances are that the object would be outside the field of view of your scope, and you would have to search around for it. It might be better to get to know the night sky and use the well tried "Star Hopping" technique to find things.

I'm sure you will soon receive plenty of advice (from those memebers who are much more expereinced than me).

Try looking at the tutorial first anyway.

Best wishes,

philsail1

http://www.themcdonalds.net/richard/...uatorial.shtml

[barkis]

Hi. Crovaz.

Like Philsail, and many others, I am not a fan of these small circles. They are very fiddly things, and not all that accurate, particularly as they depend to a large extent on your polar alignment being spot on. You will spend an inordinate amount of time on them, and they are not worth the effort IMO.

Although it can be a lengthy learning process, finding very faint nebulae can be acheived by the star hopping method. That is , using the brighter and well known constellation stars to navigate yourself around the sky. A more satisfying way too.

If you are equipped with a good finder scope, then together with a good book like "Turn Left at Orion" You can turn yourself into an expert at finding targets.

Ron.

[ashenlight]

Hi Crovaz,

I side with Ron here, he made a very valid point. I struggled for quite some time after acquiring my scope with understanding the setting circles and my frustration at their inaccuracy. Once I heared of the star hopping method (thanks to member Andrew*) this made finding my way around the sky fairly 'easy' and pain free.

Each time I go out observing I line my scope up onto Polaris (I don't worry about setting circles, getting it accurate etc), then once I can see Polaris in my FOV, I loosen the RA and DEC axis and swing gently until I find my desired target in the FOV - using a finder as Ron suggested. As you are already lined up on Polaris, you will be able to just use the RA fine adjustment cable to 'track' the object across the sky for a while. As the polar alignment is not accurate, and neither is this method really, the object will not remain in the FOV indefinitely, but I have often got a good 15 minutes of just twirling the RA cable to follow the object throughout the sky. The first object I reached with this method was M81 and M82 - fairly close to Polaris and do not require much movement.

Key to this method is, as Ron mentioned, a good finder scope - I just use the standard red dot finder that came with my Skywatcher telescope - it does the job brilliantly (follow your manuals instructions on how to accurately line up the finder to make it easier to locate your targets)

I do not use Turn Left at Orion myself, merely because I have not yet bought it, but I have heard brilliant reviews from various members on this book, so I would recommend getting it, to get you started.

Do not make the same mistake as me and think the only way you are going to find those targets is to accurately use the RA and DEC circles - follow what myself and Ron have suggested (the star hop method, and, if you want to, lining up on Polaris so your target will stay in the FOV for longer) and you won't go far wrong.

Perhaps for now start on trying to find a few well known targets using these methods, why not try M13, M57 and M81 and M82? Let us know how you get on

Hopefully some more members will come forward with their suggestions

Amanda

[crovax]

Hi, thanks for all the help! In reality I simply didn't realise that the circles are that bad. The star hopping method is something that I did naturally when got my scope and launched star software on the laptop. But I was hoping that coordinates will be more precise. Since it's not true I'll just give up and will continue improving my star hopping skill. My finderscope is very bad so it makes things harder. It's an optical small thing that is very hard to look into and where I don't recognize sky because of some magnification and little FOV. But I am already replacing it with red dot or quickfinder.

Anyway last night was full of discoveries! The sky was perfect and Milky Way was visible in full glory. I was able to find Whirlpool Galaxy and even was able to see its small companion galaxy which I really didn't expect to see at 36x. The max magnification I managed to reach was 72x but anyway it looked awesome! Then I tested out my new EPs that at last arrived from China. I managed to get clear image of Saturn at 225x and a little blurred image at 276x (which is higher than my 260x scope limit). It looked really awesome with easily visible rings. Also a little later I got a 225x image of Jupiter where I distinguished two lines in the atmosphere. However the Jupiter was too bright to look at and that made things a little harder. I guess reflectors are just not designed for best performance at planets. Next time I am goonig to try Jupiter with moon filter. And then I went for Andromeda and after some time of scanning under Cassiopeia I found it! I really shouldn't have worried about missing it because it is impossible to not notice it! It looked like a big white smudge of light in the dark sky. I didn't ever expect that a white smudge can make me that excited and happy. The bad news is that I still can't find M57. This looks ridiculous already. I perfectly studied that region of sky but that makes no sence because of crappy finder. Anyway next weekend I am not going to bed untill I find that ring. I can't believe that I won't find it after the success I had with Whirlpool Galaxy that I didn't really hope to see in my 900mm/130mm scope.

Also I saw a bright bright meteor (around 3 times brighter than Jupiter) that blazed up somewhere between Cassiopeia and Lyra. Are we having some meteor shower these days or soon?

[ashenlight]

Wow sounds like you had a fantastic night! So glad you are getting on well. Definitely try Jupiter with the moon filter, it worked for me, so filtered out some of the blinding glow and helped to show more banding.

Those white smudges are actually really impressive aren't they

On the meteor showers, this web page lists these for June:

June 13 Ophiuchids: Radiant-- near Scorpius. Only 3 per hour but fast moving bolides are common. Duration--25 day

June 16 June Lyrids: Radiant--near Vega. Another part of May Lyrid meteor stream. 15 per hour, faint blue meteors.

June 20 Ophiuchids: Radiant-- near Sagitarrius. Rate varies from 8 to 20, with occaisionally many more.

June 30 June Draconids: Radiant--near handle of Big Dipper. Rate varies from 10 to 100 per hour

Maybe it could be a straggler from the June Lyrids? in the right place anyway!