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MyRomeo

DSO's with dslr and 300mm lens...

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Hi all, I fancy having a shot at some deep sky objects, starting with Orion Nebula as it seems nice and bright.

I've a few questions tho,

First, I have a nikon d3100 and d5100 with 300mm lens with a motorised eq mount that I can get 10s exposures without trailing quite easily from, I guess I need a reasonably high iso and lots of frames?

Second, more importantly, I live in the city and my night sky is not great. I can see Orion's Belt and can roughly target m42 but without being able to see it with the naked eye what is the best way to frame dso's?

Many thanks :)

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if you already have a EQ mount the better you  polar align the more seconds you will be able to get. you should be good though for 30 secs pointing it north. orion is getting low now i would go for something else unless you get orion for  more than an hour

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I dont know what mount you are using but with good polar alignment 30 seconds should be possible.

Again i have never owned a nikon camera but if it has liveview similar to the canon you should be able to see M42 quite easily provided you have the shutter speed set to approx 20 seconds and the ISO at the highest setting, then you can adjust ISO/speed for the actual shot.

Alan

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To give you some idea of what you can do with a DSLR and a 300mm lens, here is one I did of Andromeda.

get.jpg

This was my first attempt with the AstroTrac mount I got for Christmas. The lens is a cheap (£60) f4.5-6 100-300mm zoom lens which does not have great optics. The image was 19 subs at 2 minutes, and 7 at 5 minutes.

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I was looking at a cheap 200mm lens with an X2 on E bay to throw onto my Canon just for a laugh
I could mount it onto the scope ring and try some shots that way just for something different

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Thanks for the replies.

I saw that flikr link yesterday too, very impressive and such short exposures!

Thanks frugal too, shows it's quite possible to get good results (at least what I would say is good). Is the astrotrac just a cant barn door type mount or does it actually track too?

As for my mount it's just an EQ3-2 with motor driven RA axis. It works well with a rough polar alignment but I do need to spend some time improving that.

My lens is just a tamron 70-300 f4-5.6 that I got bundled with my d3100. It's not an amazing lens but I've had some good results in general photography with it.

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Here's something i took with my Canon 6D and EF 200 2.8 II at f/4. 105x20 sec unguided.

f881493b370dd92b0ac3698ae0d7d629.620x0_q

To get really good images with a camera lens you either need a prime lens or one of the zoom lenses that has the quality needed for good astro images.

Some images taken with Tamron 70-300, not sure if all are taken with the same as the one you have.

get.jpg get.jpg get.jpg get.jpg get.jpg

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I was looking at a cheap 200mm lens with an X2 on E bay to throw onto my Canon just for a laugh

I could mount it onto the scope ring and try some shots that way just for something different

You can take great pictures with a SMC Takumar 200 f/4 M42, they are pretty cheap too. £40-50

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Thanks frugal too, shows it's quite possible to get good results (at least what I would say is good). Is the astrotrac just a cant barn door type mount or does it actually track too?

The AstroTrac is basically a well engineered barn door tracker that sits on top of a photography tripod.

It does have an ST4 port so that you can guide in RA, but I have never used that.

Sent from my SM-N9005 using Tapatalk

Edited by frugal

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Thanks for the replies.

I saw that flikr link yesterday too, very impressive and such short exposures!

Thanks frugal too, shows it's quite possible to get good results (at least what I would say is good). Is the astrotrac just a cant barn door type mount or does it actually track too?

As for my mount it's just an EQ3-2 with motor driven RA axis. It works well with a rough polar alignment but I do need to spend some time improving that.

My lens is just a tamron 70-300 f4-5.6 that I got bundled with my d3100. It's not an amazing lens but I've had some good results in general photography with it.

I have the same mount and you should have no problems getting subs of 1 min or more with good polar alighnment.

Alan

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Here's something i took with my Canon 6D and EF 200 2.8 II at f/4. 105x20 sec unguided.

f881493b370dd92b0ac3698ae0d7d629.620x0_q

To get really good images with a camera lens you either need a prime lens or one of the zoom lenses that has the quality needed for good astro images.

Some images taken with Tamron 70-300, not sure if all are taken with the same as the one you have.

get.jpg get.jpg get.jpg get.jpg get.jpg

Nice images there - how did you get the lens flare on Orion's belt?

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Nice. 

Oddly for my spectrograph I have two old Cannon FD lenses - one f5.6 300mm and one f4 300mm. Both manual focus but that can be resolved with a stepper motor and audino..

Now phase two is looking like I'll make a change in spectroscope design.. requiring one lens and not two.. now I'm very tempted to run with the 5.6 in the spectrograph and the f4 as a wide field rig..

IIRC the f5.6 cost £30 and the f/4 was £120, here's the glass next to my 80mm A80mf vixen:

post-9952-0-48987300-1390578512_thumb.jp

Nick

Edited by NickK

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Nice images there - how did you get the lens flare on Orion's belt?

The flare is made by the aperture blades when stopping down the lens to f/4. Different lenses will produce different flares and if you either don't stop it down or use a stepdown ring in the front of the lens there won't be any :)

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Here's what I have been doing with a DLSR and a 70-300mm zoom lens.

Orion at 150mm

10830815585_ab1eff40e8_z.jpg
Orions Belt and Sword by porkyb, on Flickr

Kemble's Cascade at 300mm

8669611311_c216d7b4a4_z.jpg
Kemble's Cascade by porkyb, on Flickr

The Double Cluster also looks good at 300mm.

For finding the target I have bodged a finderscope onto my camera's flash hotshoe (details in this thread http://stargazerslounge.com/topic/206638-a-couple-more-from-my-camera-and-lens-m8182-and-m31/page-2 )

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Wow! Very impressed with these shots! Really goes to show its ability over kit.

PorkyB (love the name by the way!), that 150mm shot of Orion is fantastic, I wonder if I can achieve anything like that from my garden here in the middle of the city! I can see the belt no problem with the naked eye so should be able to at least try!

Thanks for sharing some truly great shots!

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Xplode.. Superb photos too, I love the colours in your shots! Amazing that the 70-300 is capable of that. I guess I have more to learn!

What do you mean by a step down ring to avoid flare? How/where do I get one of these?

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Xplode.. Superb photos too, I love the colours in your shots! Amazing that the 70-300 is capable of that. I guess I have more to learn!

What do you mean by a step down ring to avoid flare? How/where do I get one of these?

Only the large image is mine and it's taken with a Canon EF 200 2.8 which is pretty expensive and can't be used on Nikon's. The rest are random images i found on Astrobin taken with a Tamron 70-300mm.

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