Videoastronomy on eq platform?

[Schorhr]

Hello everyone,

I am currently thinking about getting a pd camera for video/live observation and first steps in imaging.

Two questions: I have a SW Heritage 130/650 and I was wondering if the tracking of an eq platform would be sufficient?

As the pd camera is supposedly showing a similar field to a 6mm Plössl, I was also wondering if a reducer would make any sense on this telescope?

I know the heritage is not ideal, but when using a digital camera the shroud and focus adjusting via the extension rods worked well.

I do have a 10" open structure dobsonian, but having a grab and go setup would be nice. Perhaps later a 150/750 on eq mount would make more sense.

My fiancee has a 4" Maksutov, and I have a Astro3 mount, but I have not hooked up a motor yet, and the Mak"s long focal length would probably limit it's use, even with a focal reducer due to the 1.25' focuser and secondary mirror size.

The h130p would already push the Astro3 to it's limits, so I think sooner or later a new mount would be needed...

[Laurie61]

Hello everyone,

I am currently thinking about getting a pd camera for video/live observation and first steps in imaging.

Two questions: I have a SW Heritage 130/650 and I was wondering if the tracking of an eq platform would be sufficient?

As the pd camera is supposedly showing a similar field to a 6mm Plössl, I was also wondering if a reducer would make any sense on this telescope?

I know the heritage is not ideal, but when using a digital camera the shroud and focus adjusting via the extension rods worked well.

I do have a 10" open structure dobsonian, but having a grab and go setup would be nice. Perhaps later a 150/750 on eq mount would make more sense.

My fiancee has a 4" Maksutov, and I have a Astro3 mount, but I have not hooked up a motor yet, and the Mak"s long focal length would probably limit it's use, even with a focal reducer due to the 1.25' focuser and secondary mirror size.

The h130p would already push the Astro3 to it's limits, so I think sooner or later a new mount would be needed...

I would think an accurately set up EQ platform would work at 650mm focal length. What I have found is that a focal length of around 250mm is nice for wide field and for smaller targets something closer to 1500mm is useful. If you used a .5 focal reducer it would bring you down to 325mm and f2.5. The Pd camera comes with an 8mm lens that is nice quality and I have been using that as a very wide field lens, I was using it to look at Andromeda a few nights ago, you can use this without any tracking. The 8mm lens is f 1.2 and I have been thinking about barlowing it 2-3x as it would still be f 2.4-3.6, although I have not looked at how I would do this yet

[Schorhr]

Thanks for the insight!

I was just unsure if the focal reducer would work on such a telescope.

I have set up the pd camera in Astro Tools and Stellarium, without reducer it would work on some smaller objects, but as you said, imaging larger objects would be nice - or even attaching a camera lens perhaps.

Do you have any recordings of your use with the 8mm?

:-)

Also, I noted many images I saw are overexposed, is it possible to adjust the camera contrast, gama, or the video grabber's?

[Nibor]

Marcus, This link to a Phil Dyer field of view calculator for his PD camera may be of interest - like yourself I am interested in the PD camera I shall watch this thread with interest:- http://www.astrovideo.co.uk/

[Schorhr]

Thanks, yes I have seen that site, very nice tool prior to setting up the camera in Stellarium :-)

Now I'm off to search for posts of people using a 130/650 with focal reducer :-)

[Laurie61]

Thanks for the insight!

I was just unsure if the focal reducer would work on such a telescope.

I have set up the pd camera in Astro Tools and Stellarium, without reducer it would work on some smaller objects, but as you said, imaging larger objects would be nice - or even attaching a camera lens perhaps.

Do you have any recordings of your use with the 8mm?

:-)

Also, I noted many images I saw are overexposed, is it possible to adjust the camera contrast, gama, or the video grabber's?

I have a video here which I recorded onto a DVD at the time, unfortunately I have not attempted to upload video to a host for others to watch but if you have a look at my thread I have put some images in there which I extracted from the recording on the DVD. http://stargazerslounge.com/topic/193978-new-pd-camera-arived/ They are quite basic with no dark's being subtracted and just a few frames stacked. The factor to take into consideration when using a focal reducer would be how much focus adjustment you have on your scope, newt's can struggle with enough focus adjustment unless they have been modified for astro photography.

[Schorhr]

Oh, I have seen those, but where some taken without tracking?

My problem when searching for info on this camera is it's relatively new and/or reviews are done with larger apertures and/or show only stacked images ;-)

I'm interested in the live aspect of such a device. Should I just search for a Samsung or similar camera on youtube to get a close idea of what to expect?

[Laurie61]

This is one taken of Andromeda without tracking, using the 8mm lens. 6 frames stacked and levels adjusted.

[Schorhr]

Neat!

I hope that the light pollution here will not cause too many troubles.

Do you still have any single frames?

Thanks!

[Laurie61]

This is a single frame, no adjustments. The view you have on the screen, when viewing live, can be adjusted by using the camera control and also the TV picture adjustment.

[Schorhr]

Thanks, that's better then I have expected :-)

It will be nice to experiment with some older f/1.4 camera lenses 50 and 70mm.

Too bad I gave away my usb video grabber last year, but at 5-10€ they are not too expensive.

Didn't astrophoto.co.uk offer a focal reducer as well? I can't find it on the ste anymore.

Perhaps I'll just try a cheap one such as http://www.ebay.de/itm/1-25-0-5x-Focal-Reducer-for-telescope-eyepiece-/200876681138?pt=LH_DefaultDomain_0&hash=item2ec52ee7b2 and I see sky's the limit has some affordable ones as well.

[Laurie61]

Yes I think 50-70mm lens would produce some nice results. I noticed Phil Dyer is selling some video lenses for about £30 delivered which look quite interesting, 25mm f1.4 and 35mm f1.7 http://www.astrophoto.co.uk/lenses.htm I might be tempted by the 35mm

[Schorhr]

Yes, tight budget though... As usual ;-)

[Carl Reade]

Hi I tried a focal reducer on my SW 150p and no good with video. The CCTV lenses are good for wide field 2mm to 12mm.

I'm now trying an adapter for old SLR lenses and it looks like a better option for larger objects like M31 etc and comets.

If you go above CCTV lenses then your into tracking from what I have found.

Carl

[Schorhr]

Hello Carl,

what reducer and which telescope (150/1200?) was it?

It would be nice if a reducer would work to film larger DSO.

I did try tracking with the DSLR of my fiancee on the eq platform and the 130/650, it did certainly work for 5 seconds, perhaps for 10, but before I got the speed and setup adjusted those clouds covered the entire sky out of no where ;-) The short focal length of the telescope is really great, and with the right HR Planetary it's still a great portable allrounder.

I have seen a few videos on youtube with the Samsung camera, I suppose I should give the pd a try even if it means I will have to get a tracking mount one of these days...

[Carl Reade]

Hi Marcus, the scope is the 150p/750mm F5 on the Eq3/2 goto mount. What I have found so far is,

With camera direct on the scope globs, and most DSOs will fit in the FOV nicely, perfect for the whirlpool galaxy and Bodes galaxy. The likes of Andromeda being much larger the core just fits in the frame. (tracking is a must)

With a standard CCTV lens 2.8 - 8mm it is very good for widefield with results similar to Lauries. I currently use one of these lenses on a meteor cam I have recently set up (no tracking required)

More recently I purchased an adapter for attaching my old camera lenses like and 80 - 200mm zoom. The purpose is to capture the full Andromeda and Orion neb. Testing is still in progress due to the weather. The findings so far are, they focus no problem and the larger object fit no problem but when into these lenses tracking is a must or you will just get star streaks across the screen.

It appears not many people have had success with reducers and newtownians, me being one no focus at all just a picture of the secondary mirror, they seem to be better geared for other scopes. So I opted for SLR lenses for the between widefield and high mag.

Hopefully of use Carl

[Schorhr]

Well, I guess I'll try and if all fails I'd get a more rigid eq mount later.

Or if I can get a cheap used goto mount, but right now that's out of the question ;-)

But perhaps the eq platform will be enough on 650mm.

[DoctorD]

Hi

Reducers move the focus point in towards the primary, newtonians designed for visual sometimes cannot ascribe focus in this configuration because the focuser cannot move that far in. The solution appears to be to live the mirror cell up the tube - although I have no experience of this.

HTH

Paul

[Schorhr]

Hello Paul,

with the heritage 130/650 I can't even get into focus with a digital camera and my selfmade adapter, but as the Flextube can be shortened, this problem does not exist with this telescope ;-)

So I am confident it coukd work, I just was not sure if a reducer on such a "fast" telescope would make much sense.

I know reducing the tube's length is not ideal without changing mirror size, and the h130p has some other issues, but I'd like to try with it as well as with a Mak, but with it's long focal length I'm worried tracking won't be possible that easily, the high magnification would be a problem, and the aperture is smaller as well...

[Laurie61]

Hello Paul,

with the heritage 130/650 I can't even get into focus with a digital camera and my selfmade adapter, but as the Flextube can be shortened, this problem does not exist with this telescope ;-)

So I am confident it coukd work, I just was not sure if a reducer on such a "fast" telescope would make much sense.

I know reducing the tube's length is not ideal without changing mirror size, and the h130p has some other issues, but I'd like to try with it as well as with a Mak, but with it's long focal length I'm worried tracking won't be possible that easily, the high magnification would be a problem, and the aperture is smaller as well...

I think your best scope is the 130mm f5, more aperture than the Mak. If you want a longer fl it would be better to barlow the 130, if you fitted a 1.5-2X barlow the f, at f7.5-f10, is still less than the Mak.  

[Schorhr]

I would be happy with 650 or 325mm focal length due to the fov of the camera ;-)

[shirva]

A nice wee ed80 Your best option lol...Davy

[Schorhr]

Another telescope and the Lady will Beat me up ;-)

[Laurie61]

Short term pain, long term gain.  

[Schorhr]

So I have ordered it (without accessories), despite the currently low budget...

I hope I don't have to sell other stuff and am able to use it like I intended.

I do have a BNC/RCA(cinch) adapter, but what is it? This way around?

http://www.ebay.de/itm/Adapter-BNC-Stecker-auf-Cinch-Buches-Chinch-/281117503755?pt=DE_Haus_Garten_Heimwerker_Sicherheitstechnik&hash=item4173e8b10b

or http://www.ebay.de/itm/Koaxial-Adapter-BNC-Kupplung-Cinch-Buchse-Female-Female-/360386445642?pt=DE_Computing_Monitor_AV_Kabel_Adapter&hash=item53e8b4c14a

Looking at http://www.nightskies.net/scopetest/accessories/video/video.html it seems like I need the first type. Oh well, then I have to order one for €1.

Regarding the usb video grabbers: I do have a basic one here (something like http://www.amazon.de/Apollo23-Easycap-4-Kanal-USB-Video-Sicherungs-Adapter/dp/B00CX8U6BU/ref=sr_1_3?s=ce-de&ie=UTF8&qid=1379814868&sr=1-3&keywords=usb+dvr ), are there any better or worse ones? They all look like they came from the same factory with different lables.

Any ones with low framerate but lossless compressed stream?

What I wasn't sure of (and I did not want to bug Phil anymore as I emailed him twice, I was unsure if my mails end up in people's spam folder gain): Is the non-kit version already ready to fit in a 1.25" focuser, or do I need to make my own adapter?

Thanks everyone!