Guiding at last....

[adman]

I have been into astro now since last August, and things have been gradually coming together both knowledge and gear-wise, and tonight I have been able to take my first guided shots (see below) through my 8" newt - and it felt goo-ood! :D

My guidescope leaves a lot to be desired - but for the moment it will do the trick - just.

I started with a little moonage just after sunset and then tried to get M42 before it went behind the trees, but as it was my first time it took me a while to get everything going, so I swung over to eta carina.

Here are the best of my shots. Single subs only. Most of the others had issues with guiding, but for my first time I was glad to get one frame where the guiding went OK. I have cleaned them up a little in photoshop - just levels mostly to remove light pollution, and I ran the moon shot through the sharpener just to make those craters stand out a little better.

Thanks for looking - any feedback appreciated.
Cheers
Adam

[cybereye]

Adam,

Great shots - I'd love to hear what your setup is for guiding as I'm facing a similar issue and challenge.

I got caught out last night - when I got home it looked like it was clouding over and so decided not to set up the scope. Guess what, when I checked later in the night it was beautiful and clear!!

No need to thank me for the clear sky you had to take these images...:)

Cheers,
Mario

[adman]

Thanks Mario

its mostly the guidescope that is the issue. It's a department store special - a 60mm Celestron that I am pretty sure has a plastic primary lens. It was bought for my 7 year old son by his grandparents. It was so hard to use with the dodgy mount etc that he quickly lost interest. I used it to learn how to drift align before I got my newt, and have pressed it into service again as a guidescope.

Attached to that is my QHY5 guide camera which I used with PHD, with the camera connected directly to the ST4 port on the mount. I tried it through EQMOD last night, but didn't have any success - but I think the problem there was me - still learning....

What are the issues that you have been having?

Adam

[cybereye]

Adam,

The main issue I've been having is funds!!

I haven't tried auto-guiding yet but will soon have all the necessary bits and pieces in place. However, I've been told that my bodgied webcam that I intend to use may not be sensitive enough to use for guiding. Time will tell and I'll cross that bridge when I come to it!

Mario

Just had a look outside - what a surprise, it's cloudy again!!!

[monoxide]

well done, looks a lot better than my first :)

take baby steps when getting used to guiding, theres nothing more frustrating than trying to image when your guiding isnt playing ball.
take 1 night just purely to get your guiding sorted out and it will pay off 10 fold.

this way you can get your guiding dialled in, when you go to image you will know exactly whats going on and why

[RobF]

Nice going Adam. Both pics nice and crisp.
I agree with TJ you need to invest time into your autoguiding - its a good thing to experiment with when the moon is about ;)

The doors to the treasure trove are swinging open now you've got guiding under way!
(can I hear a faint cash register sound in the distance too...?)

[freespace]

Congrats Adam! Those are really nice images :D

As a PHD user who has still to get this whole thing going, I have a question for you: do you remember what durations PHD used when guiding?

Down the bottom in the status bar when guiding, it says something like

E dur=xxxx dist=yyyy

Where xxxx is the last guide pulse duration in ms (I believe) and yyyy is the distance in pixels of how far the guide star has moved.

For me PHD is using dur=1000, so 1 second guide pulses, but my guide star keeps drifting steadily away anyway. I think this is due to atrocious polar alignment (I have problem doing a drift alignment due to where I setup tonight - basically no western or eastern horizon views).

Cheers and congrats again,
Steve

[adman]

Thankyou - more luck than expertise at this stage I assure you...:P



Thanks Rob - bear in mind that this was the best of about 20 frames - some of the others were seriously ordinary - didn't even get enough to stack. So there's lots of experimenting to come.

The doors to the treasure trove are opening, but they key seems to be stinking great wads of cash. On my short-term wishlist:

1. Better focuser. I am amazed that I got near focus at all as the standard SW focuser shifts the focus about a mile when you use the locking screw. Not to mention how it tilts the drawtube as well. would settle for WO focuser, but would prefer motorised moonlight....

2. Better (waaay better - 80mm triplet apo if I can get one) guidescope to replace the department store special currently in use - see pics below..

3. MPCC to stop your images making it look like you are zooming through hyperspace...:)

So thats at least $1500 as far as I can see - and don't even get me started on my longer-term wishlist.






Thanks!

The only thing I changed from default settings was the DEC algorithm - changed it to "Low Pass Filter" (and I don't even know why :P ), and the camera exposure - I think used 0.5s. Initially the DEC graph was all over the place which could have been alignment, balance, worm gear etc as I didn't check any of those things - just wanted to give it a whirl and check that all the bits talked to each other.

[bmitchell82]

adman... :) you don't need stinking wads of cash to do what you need to do. You have a skywatcher focuser? use that as your guide scope, PHD is capable of sub pixel guiding that means you can set minimum pixel movement to .15 of a pixel.

I have done the same and with the f4.72 10" the finderguider is f4. its a simple matter of matching the thread to the back of the finder and removing the finderscope eyepiece. Ill take some images for you on this one and post them up sometime over the weekend.

I currently use the craford style of focuser but you have the blue tube so it looks as if you have the rack and pinion style, look at a moonlight focuser for just a bit over 200, it will serve you well. all up you can get away with the whole rig for just >$300... not thousands.

http://www.focuser.com/cgi-bin/dman.cgi?page=category&plugin=dstore.cgi&category=3

peter tan has MPCC's for 100 dollars less than anywhere in aus

www.tan14.com youll find it there. 170 i purchased mine for recently

another piece of advice unless you have money to spend, spend wisely untill you know for certain what you want to image, the setups change dramatically depending on your desired targets.! its taken me more than a year to make sure of what it is that i want to image, now its a case of uni student budget to make things start happening. see my threads on turning the sw 10" into a astrograph. slowly but surely itll happen.

[multiweb]

Good stuff Adam. Your keyhole is terrific! :thumbsup: Not gonna comment on how you should guide because looking at your pic you're the one who should telling me how to guide :lol:

[RobF]

I think Brendan means "skywatcher finder"
This is still on my to do list - I think sometimes budget necessity can force some clever innovation. If Brendan's images are anything to go by you certainly don't need an expensive (and heavy) guidescope necessarily Adam......

Brenden - did you have to make up a fitting to screw into the finder, or cut off anything?

[adman]

Thanks for the advice Brendan. I wouldn't mind trying the finder-as-guider idea. WOuld it work with my QHY5?? It would probably give better images than the crap refractor that I have now.

Where can I get a moonlight for that price.....I want one now...!



Thanks Marc -I have a feeling though that you may still have a thing or two to teach me...;)

Adam

[bmitchell82]

ahhh..... yes a focuser isn't a finder... Please forgive me as i was at the end of doing 4 nasty assignments for structural, geotechnical, fluid mechanics and autocad drawing :( very big week indeed.

adman, where can you get a moonlight for that price, i added a link. you can get it there.! depending on what you want to add onto it thats where the cost comes in. if you want it to be able to do motorized focusing that is where the cost comes in. so just shoot back i think the moonlight focuser starts at 160 (USD).

As for the guide scope, my first guidescope was a dick smith electronics 114mm newt, i ditched that because it was a few kgs and i got done over by one of the vanes of the secondary holder came loose, i couldn't figure why my guiding was all over the show.! so that is why i went the finderguider option. Ive added some pictures in of the setup.

No cutting was involved i hate cutting things it is a absolute LAST RESORT.there is always some way around it! and also the qhy5 will work 100% in this setup. pm me if you need a hand with it.

[freespace]

\derail

That's pretty awesome Brendan!

I have the same finder, and was using it complete with the eyepiece with a webcam I had. After seeing your setup, I was inspired to mod i to remove the eyepiece and the lens in the webcam for prime focus action, and I say: the results are much nicer!

Cheers,
Steve

[bmitchell82]

yes prime focus on these things are fine, the best thing is you can align the finder to the axis of the imaging scope :) i can generally see the object im imaging in the finderguider which helps with alignment as its such a short focal length the FOV is quite large.

glad i could be of some inspiration

[gbeal]

I'll add to that as well, mine is an old generic 50mm finder, without eyepiece, and currently has a Loddestar guider in it, but previously I used a DMK. Simple, lightweight, and if the guide camera is a "fixture" in the guider there is less chance of a dodgy focuser giving any form of flexure.
Gary

[adman]

Thanks for the pictures Brendan - looks like a solid little setup.

Just curious though - why did you have to remove the locking ring from the helical focuser?

Adam

[bmitchell82]

to allow enough back focus. it only just makes it :)

[adman]

ohhh I see now - had to look back at the first picture where it is screwed all the way down...

Also - did you have that gold ring custom made?

Adam

[bmitchell82]

yep i did it myself. i've got access to some really good gear! ;)

[RobF]

Wish I had the gear, brains and know-how.
Thinking of trying to gerry rig something with plumbing plastic adaptors from Bunnings.

[freespace]

Being an engineer-in-training, I applied duct tape :D

Luck also plays a part: the quickcam connect's lens "nozzle" fits right into the base of the finderscope.

[alistairsam]

Hi,
I've tried to do the same with a Microsoft Lifecam and a Creative Vista Webcam as well, but in both cases can't achieve even out of focus video to say I need more infocus.
will prime focus work only on certain webcams? or is it to do with alignment of the webcam's ccd sensor to precisely the mid plane of the finderscope?
what else would be required to interface with PHD

[adman]

I think that you will need to remove any lenses on the webcam itself so that the sensor chip is at the focal plane of the scope.

I am far from expert in this though - maybe someone else can chime in ...

Adam

[alistairsam]

hi,
thats what i did.
i removed the lens from the webcam, and the eyepiece or primary of the finder. no joy.
also tried it with a celestron 60mm refractor without its eyepiece, also tried with a newtonian without its eyepiece, but in all cases, i was holding the webcam and trying different focal points. so not sure if it has to be very precise since the ccd chip is quite small.

[adman]

it might help to know the rough position of the focal plane first. Aim the scope at a nice bright subject (not the sun - just an outside scene will do), then without any eyepieces and with the focuser (if any) racked all the way in, then see if you can get an image in sharp focus projected onto some tracing paper. This is the focal plane. Make a measurement so you know where it is then try the webcam sensor at the same distance.

You might also need to adjust the webcams exposure settings to get a better image....

Can anyone else offer any suggestions??

Adam

[bmitchell82]

go to a bright star, way easier, you put it there in the center of the FOV then you can hold the ccd by hand and move in and out you will see if you have enough travel in because as the star becomes focused it gets smaller and smaller, and on the other side it gets bigger. if it gets smaller and smaller and doesn't get bigger again, you havn't got enough infocus.

If your looking to auto guide you have a mount that can already track, so that makes it alot easier.

Trying to focus on something in the daylight hours means nothing really as its not at infinity, the focus is at a different point.

Even when looking towards the moon Vs the stars... its a different focal point! :) hope that helps and good luck

Brendan

PS, if your using a webcam at focal point, i think that you might have to remove the lense of the camera, as it changes things quite a bit, look up the Philips toucam and the modification to get it opperational at prime focus that should get you kicking. if not look at getting a second hand Meade DSI or orion star shoot autoguider, thats the best option if you are wanting to do DSO guided photography!

[alistairsam]

thanks. will try again using a bright star.
where can we get the phillips toucam or second hand DSI's?

[bmitchell82]

most of them can be found second hand now, as they arnt new, and have been superceeded by about 2 or 3 generations. keep your eyes peeled. although the orion star shoot auto guider OSSAG, is about 300 350 at bintel i think? if not try qhy5 from theo or myastroshop.

[RobF]

There's a toucam going in the classifieds right now for $105
http://www.iceinspace.com.au/forum/showthread.php?t=61644

QHY5 went off the other day too...

[adman]

did you have any luck finding the focal plane??

Adam

[alistairsam]

Hi yes, I did find the focal plane with the paper as suggested, am just waiting to check with the webcam without the lens and without the finders objective.
i did try it with an slr as well without its lens and looks like i do have sufficient infocus for the webcam. this is the finder on the bintel 8" dob newt.
will post results. waiting for the sky to clear as well.
thanks