A few questions from a beginner.

[Steve789]

I've been obsessed by this new hobby for about three weeks now and have managed to get in at least 3 nights observing a week and dabbled a bit with some astrophotography. In this short time I've amassed a few questions that I haven't found the answers to so here goes. Sorry if they seem a bit dum particularly number 2.

1.My equipment consists of a secondhand skywatcher explorer 150p mounted on a EQ5 with a single axis clock drive and a Canon 300D DSLR. The EQ5 is black and has a plastic accessories tray and hinged spreaders on the tripod (see picture attached). I'm guessing this is an older version than the current one which is white and has a metal tray and is bolted through the middle of the mount. The newer version looks much more solid as my tripod legs can flex in and out quite alot. My question is can I buy just the accessory tray/bolt parts anywhere to upgrade mine to the new spec?

2. When I've been doing long exposures (I consider 1 minute to be a long exposure) I stumble around in the dark because I'm worried about the dim red light from my head torch affecting my image. Should I worry about this? Would the light from my laptop screen or my mobile phone affect the image in any way?

3. I use a remote shutter timer with my Canon 300D. How long an interval should I leave between exposures?

4. Does anyone else use similar equipment to me and thread the DSLR T adaptor directly to the focuser by removing the 1.25" piece from the focuser? I've found the Astronomik clip in filters online but is there a cheaper alternative arrangement to use filters with my setup? They seem quite pricey and if I ever change to a CCD in the future they'll be useless.

Thanks in advance for any answers.

[Ruud]

If you don't extend the legs and if you tighten the bolts at the top of the legs really well, you might get a more stable tripod.

Also, after you put it down, you could try pushing the legs out a bit, putting a little tension on them. That makes them more ridged too.

The tray serves no function for the stability of the tripod. If you remove it and hang a bag full of bricks between the tripod legs, the whole becomes steadier still.

If you glue some soft silicone plastic on top of washing machine vibration pads, you have an inexpensive but effective way to isolate your setup from vibrations from passing traffic, etcetera.

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of course, a spreader to put tension on the legs would make a big difference. But I have no idea if you could fit one on your tripod.

[Ruud]

I see no counterweight on your mount. Do you have one? It helps a great deal if the telescope is well balanced.

[baggywrinkle]

If you can get a good polar alignment then exposures in excess of 1 minute should not be a problem.

The best way is to take a >1min exposure and see how it looks, are you getting star trails? Under/over exposed?

I would allow about 20 secs between shots to allow the imaginging sensor to cool a little to reduce noise.

Get ba copy of Make Every Photon Count' UK published and well thought of on this site.

[jambouk]

1. Contact FLO (unless anyone else gives the answer here) to see if the white legged tripod for the HEQ5 fits this mount.

2. Trial and error. As long as you are not shining te ted light towards the opening of the telescope you will probably be ok for a few seconds. Why are you stomping around whilst it is imaging anyway, especially if the legs are flimsy, you'll just run the risk of introducing vibration artefact. Set it up, start it running and step away and leave it; if you want to do observing with naked eye or binoculars at the same time, do it in another part of the garden.

3. Again trial and error. I leave 2-5 seconds. You can leave as long as you want, but if it's too long you are wasting valuable time you could be capturing data. Darks will help get rid of some of the artefact generated by a warm sensor. With 60 second exposures you want to capture as many subs as possible (>200) so you don't want to add an extra 20seconds x 200 on to the imaging run in my opinion; i'd rather shorten the gap to 2 seconds and then use the saved time to capture dark and flat frames.

4a. I've seen it done yes. Again trial and error. Experiment.

4b. The filters retain their value reasonably well so you could easily sell them on. If you screw the t ring straight to the t ring you'll have to go for a clip filter. If you use a nose piece, 2" or 1.25", then you could get the relevant sized filter to screw into the end of that; there are lots of types of LP filters, and the moon and sky glow one i have (baader) is pretty good.

Good luck with it all and look forward to seeing your images.

James

[Cornelius Varley]

I'm not sure that the spreader plate used on the latest version of the mount will fit your tripod. The current spreader plate is attached to the tripod using the long bolt that holds the eq head to the tripod, so you will have to replace that as well.

[Steve789]

Thanks for all the replies. I'll try doing some of my own mods to the tripod to see if I can get it more stable. Tightening the bolts is a good idea, I don't know why I didn't think of that.

I do have a counterweight for the scope which I take off for moving the tripod in and out of the house. I was in the process of setting up when I took that photo.

I was experimenting with exposures up to 2.5 minutes last night with 20s intervals but started to get star trails with a very rough polar alignment. I can see I will need to master polar alignment in the future but for now I'm having enough fun experimenting.

It looks like I'll probably go for the clip filter as I don't think I can get focus if I use a nose piece. I might give the bank balance a chance to recover first as a DSLR with live view will undoubtedly be on the cards soon.