1100D settings advise for Comet Lovejoy

[Icearcher (Chris)]

Hi All

I'm borrowing an Eos 1100D over the weekend with an 18-55mm and 55-250mm lenses. Ill have a tripod and hopefully a nice dark site about an hour out of the city.

I would like to get some nice shots of the comet, hopefully a bit zoomed in if possible as well as wide field shots.

What would you recommend for settings, exposure times, ect? Any tips and tricks would be welcome.

Regards
Chris

[Camelopardalis (Dunk)]

Welcome Chris!

I'm certainly no expert - but I think your challenge is going to be tracking, unless you're using a star tracker or equatorial mount. At the longer focal lengths you'll be seeing trailing stars after a couple of seconds without one. Use the image review and zoom all the way in to see this. Maybe start at the 55 end and see how far you can push the exposure time.

I find the ISO sweet spot on the 1100D to be about 1600 for long exposures (a couple of minutes), although the only thing you can really do is experiment...without tracking you're going to need to pump up the ISO, but you should be OK as the short exposures should keep the noise down.

The other thing is take LOTS of pictures, one after the other. 20-30? More is more! Then stick the lens cap on. Take a similar set. With these you can use a program called Deep Sky Stacker to add all the frames together and see what you get.

Good luck and keep us posted!

[ShOrEbReAk (Troy)]

welcome Chris

I am only new to here and the guys have been great! they have helped me out heaps, so much knowledge here in these forums.

As to the comet I Still cant find it hahahahahahah

best of luck in your search.

Troy

[Icearcher (Chris)]

Thanks Dunc, I wont have any tracking tools unfortunately, the best i will have is a tripod.

I was thinking along the stacking path as well, any idea how long i should expose for to get a good bunch of shots to stack?

Hey Troy, Iv managed to catch the comet in my binos, im in the inner west and looking over the city. I can just make it out as a tiny fuzz ball when its high in the sky, it takes a bit to track down but its there.

[ShOrEbReAk (Troy)]

chris

how did you go? if you did see it where was it? I have been looking in lupus and to the side of it with no luck. That is where EySkye keeps telling me. Also upgrade to pro for 5 bucks for heaps more objects in the catalogue and a handy strap your phone to the telescope and calibrate of planets and moons!

Troy

[doppler (Rick)]

Here's a pic taken with a 1100d and 135mm lens. This is a single pic straight from the camera. iso 1600 20 seconds at f 2.8. The camera was piggy backed on a scope so you would have to use shorter exposures to avoid trailing.
Rick

[Icearcher (Chris)]

Hi Troy, haven't got the camera yet, grabbing it from work tomorrow. The comet should be about the separation of Rigel to the belt but the other way. I think the light pollution from the city makes it very hard to pick out.

Hi Rick, thats a nice pic, its encouraging to see what can be done without the telescope optics. Hopefully stacking lots of short exposures will give me something similar.

[Camelopardalis (Dunk)]

Yeah there's a "rule of 500" which is a rule of thumb for how long your exposures could be before showing star trails. It says that if you divide 500 by the focal length of your lens, you'll then have the time in seconds that should work. IMO use it as a guide and see how you get on. The 1100D has quite large pixels so you might get away with slightly longer.

Here's an example...at 55mm, the focal length is really 88mm because the 1100D has what's called a "crop sensors", i.e. smaller than a full 35mm frame, and this incurs a "crop factor", for Canon APS-C sensors this is 1.6 (55 x 1.6 = 88).

So if we divide 500 by 88, we get 5.68s ... so give it a go at 5 and 6 seconds and see how it looks. The comet is pretty bright, so it should show up quite distinctly compared to the background stars even at that exposure length. A couple of weeks ago I took a couple of shots with my 1100D@ISO1600 and at 15s the Comet was very obvious as a bright green blob with my small telescope (350mm focal length)...admittedly from a dark site...but give it a go!

As for stacking...it's a tough one...I don't know if you'll get hints of the tail from those lengths of exposure

[Icearcher (Chris)]

Thanks Dunk, at 255mm im looking at 1.5sec so I might have to give that a miss. Ricks pic does give me hope that around the 150 might work quite well.

Im going to do a few tests tomorrow night from the back yard, see what i can get without trails.

[Icearcher (Chris)]

Update from a bit of testing.

Was shooting from my back lawn, inner suburbs in adelaide and still managed to just grab the comet, Don't mind all the horrid light pollution, also, the moon wasn't helping at all.

Got the green colour and a half decent pic of orion too.

[Camelopardalis (Dunk)]

Nice one Chris, all you need now is a star tracker and you'd be good to go but if this was only 1.5s

[Suzy]

Originally Posted by ShOrEbReAk

chris
how did you go? if you did see it where was it? I have been looking in lupus and to the side of it with no luck. That is where EySkye keeps telling me.
Troy

This is an informative thread for me as I too have a Canon 1100 & wanting to take piccies, so thanks guys .

Hi Troy,

The comet is super easy to see in binoculars from light pollution and even the full Moon close by. To see it with the unaided eye will require a dark location and it will appear as a small, round fuzzy spot.

It's easy to find using the finder chart in the link below. Scroll down the page to January's map & click on the link below it for the large black & white printer friendly pdf:
http://www.skyandtelescope.com/astro...ght-122920141/

On January 11th, it'll be at its brightest.
This article for the ABC was written by IceInSpace member, Ian Musgrave who also writes for Astroblog. It's a very informative article and he gives us a step by step guide for star hopping to find it. I've used it- and it's very easy to find using his directions.
http://theconversation.com/comet-c-2...s-sunday-35900

All the best Troy, and happy comet hunting!