Calling Capt. Chaos, calling Capt. Chaos...

[Kenny_10_Bellys]

In the welcome forum you mentioned you would happily give advice on astroimaging using a D50. I need it, because so far I've sucked at my attempts and it's quite frustrating to someone used to taking semi-decent images. Here's what I've got and what I've found...

I have a Nikon D50 and a Meade ETX-105PE. I have a prime-focus adaptor that can screw in the back of the scope, or I can use a 2x barlow with a T-adaptor ring to try and get shots through the eyepiece at higher mag for planets.

1. Mirror slap ruins any short exposures. For mid-length I simply stand in the way till the vibe dies down and then move. Far from ideal.

2. Focus is a bitch. Once strapped on you can be sure the scope needs realinged to target and that focus is wrong, but given the dim view through the eyepiece display it's proven almost impossible to target and focus adequately.

3. I cant piggyback. I just ordered an astro-engineering camera bracket to piggyback, but as I have the PE version with the LNT sensor unit and built-in red dot sight that fouls it completely. It might fit on backwards, but then I cant see to target the scope and anything above 20 degrees would be a no-no.

I've gotten so bugged that I've ordered a Lunar Planetary Imager to plug in and take images with. At least with that I can get a real time 640x480 for targetting with focus assistance, can use it for tracking if I find a way to piggyback and the software also supports auto aligning and stacking. It also neatly avoids mirror slap too. I cant wait, but the sodding thing is taking ages to arrive.

If you have any advice or ideas I would love to take some nice shots with the D50, but right now i cant get around the problems described above.

[geppetto]

Kenny

I'm amazed that the ETX can move properly with a DSLR on the back.

We tried the same sort of setup for a mate of mine and the whole

thing was a disaster.

Tracking was non existant. The ALT clutch kept slipping even after a clutch

mod and proper balancing.

You'll get more results and fun using the LPI I reackon

[russ]

Kenny, i think you are on the right track with your Refractor idea in the other thread. You'll get much better results with a small refractor on a driven EQ3 than you'll ever get from an ETX. The ETX with the LPI will be a much better proposition for lunar and planetary imaging.

For the D50 concentrate on finding a small EQ mount. Either use it for widefield with the D50 and lens. Or prime focus with a small refractor.

In the other thread, i suggested an Antares Sentinel 80 for £179 brandnew. You should be able to nab an EQ3 with drives for £100-120. That would be a good setup for the D50 and within your £300 budget.

Russ

[Kenny_10_Bellys]

Are we talking about mounting the D50 direct to a mount as well? I imagine it would need an adaptor of some kind to do that, right? I'm definitely going the refractor and equatorial route to try and get my widefield kicks, and I'll use the Meade and LPI for my planetary imaging. One day in the far future when I get my 10" SCT I'll use the refractor and LPI as guide and slap my D50 to the back of the SCT at prime focus. I'm thinking ahead here, but have not yet figured out how to afford it.

I'll go check out that 80mm APO you're recommending Rus, and have a look for a driven mount. Back later...

[Kaptain Klevtsov]

In the welcome forum you mentioned you would happily give advice on astroimaging using a D50. I need it, because so far I've sucked at my attempts and it's quite frustrating to someone used to taking semi-decent images. Here's what I've got and what I've found...

I have a Nikon D50 and a Meade ETX-105PE. I have a prime-focus adaptor that can screw in the back of the scope, or I can use a 2x barlow with a T-adaptor ring to try and get shots through the eyepiece at higher mag for planets.

1. Mirror slap ruins any short exposures. For mid-length I simply stand in the way till the vibe dies down and then move. Far from ideal.

2. Focus is a bitch. Once strapped on you can be sure the scope needs realinged to target and that focus is wrong, but given the dim view through the eyepiece display it's proven almost impossible to target and focus adequately.

3. I cant piggyback. I just ordered an astro-engineering camera bracket to piggyback, but as I have the PE version with the LNT sensor unit and built-in red dot sight that fouls it completely. It might fit on backwards, but then I cant see to target the scope and anything above 20 degrees would be a no-no.

I've gotten so bugged that I've ordered a Lunar Planetary Imager to plug in and take images with. At least with that I can get a real time 640x480 for targetting with focus assistance, can use it for tracking if I find a way to piggyback and the software also supports auto aligning and stacking. It also neatly avoids mirror slap too. I cant wait, but the sodding thing is taking ages to arrive.

If you have any advice or ideas I would love to take some nice shots with the D50, but right now i cant get around the problems described above.

Mirror slap is cured as you say by getting in the way or putting something in front of the 'scope until it stops wobbling.

Focus is a real bitch indeed. I downloaded a trial version of camera control pro from nikon, this allows full screen images to be seen on the screen as soon as the image is taken via the USB lead. You can then snap away adjusting the focus until its good, bin all the test shots and you're off. The software allows you to change shutter speed and trigger the shutter from the laptop, up to the slowest shutter speed available of 30 seconds. It also has a time lapse option to shoot frame after frame until you tell it to stop. This is very good for when you stack the images and average them to get rid of the noise caused by ISO1600 etc.

I also got hold of a Stiletto focus aid which has a Nikon camera bayonet on the end, you use it in place of the camera to focus, swap for the camera and you are supposed to be set. Didn't work for me at all.

Have you tried a Hartman mask? Basically a front lid with two holes in it. When the two images formed through the holes line up, you are in focus. Easy to make out of a shoe box lid, it just pops on and off.

Once you have the images in the camera or laptop you need to stretch the image in photoshop or similar to be able to see anything, most of my shots look like black frames with a couple of tiny dots to begin with.

Filters are your friend if you have red skies because of light pollution, try the Baader neodymium one or the CLS filter. These will get rid of the nasty streetlight effects.

I'm not familiar with the ETX personally, but at f/14 I'd expect really really long exposures to be the order of the day. My images are mainly done at f/5 or faster so f/14 would need 8 times the time to get the image. You will be looking at 4 minutes ish, which is really too long. You could try a focal reducer to speed up the imaging a bit.

My Mak. is f/14 and only used for lunar / planetary imaging as oherwise the exposures run into minutes and the guiding / alignment has to be spot on for that to work.

On the web the ETX shows up as having a wedge on top of the tripod, this will help get rid of field rotation if you can line up the (normally) vertical axis to Polaris so that the tube rotates with the stars - really required for long exposure stuff.

Pulsar Optical have a tiltable piggyback adapter on their website, I have no idea if that's what you have already, or if it might work.

HTH

Captain Chaos

[Kenny_10_Bellys]

Rus, where you finding the Antares at that price? I'm turning up bare tubes for 249 or so, never mind finding a decent mount and spotting scope, prisms, etc.

Mr Chaos sir, I didn't realise that the camera control software was actually out for the Nikon, all the versions I've seen so far have only covered Canons with provisional compatability for the D70. Had I known I would have gone for it. I was going to try making a Hartmann mask with 3 aligned segments to try and improve focusing, but since you cant see squat through the viewfinder anyway it would make no difference. Three times nothing is still nothing. With images beamed to the laptop it would be a worthwhile thing, but no good otherwise.

I've tried setting the scope into polar alignment in order to ease the drive problems, but unless I can find some way to go piggyback there's not much I can see myself getting though the scope itself given it's limitations. With the LPI I think the ETX105 will be just fine for planetary stuff, but I'm pretty much sold on the idea of a nice refractor and equatorial driven mount to get around all this. All I need is money.

[Kaptain Klevtsov]

Trial version is out and it last for thirty days (two clear nights) before you need to put in the code number. You can buy online, but it needs a working US snail mail address and zip code, which I didn't have. My copy is therefore dead at the moment. I've tried UK suppliers but they've not heard of it much less got it.

Captain Chaos