New kit for DSLR user

[Loogie]

Hello there

Being a daylight photographer over the years I've accumulated a Canon 5D Mark II and a Sigma 300 mm F2.8 with various converters. Plus a wide angle Sigma 12-24 and a Sigma F1.4 50 mm.

Seeing some of the posts on the internet I'd love to start taking pictures of the stars/ nebulas/ milky way and so on.

There are so much equipment out there I don't know where to start. I don't want a telescope (have enough to carry) but I'd like to take the whatever I get on trips too.

Requirement nr 1.

Long exposures 5 min + So I need something that compensates for the earth rotation

Requirement nr 2.

Something that will allow me to key in an object and the rest is done for me.

Any suggestions what I should get ?

These are the two I found so far

Vixon GP

Vixen Optics | GP2 Equatorial Telescope Photo Guider | 3540

Astrotrack

Astrophotography Made Easy - Home

Wouldn't mind getting something cheaper... I take it the two above only tracks... they don't find objects

Thanks for any replies.

[brendant]

Hello and Welcome to SGL.

Unfortunately even with your limited searches you have discovered that astroimaging is an expensive hobby. The Astrotrack is probably one of the best portable devices for long exposure photography but does not come cheap.

There are a couple of other mounts you could look at which are significantly cheaper than the Vixen mount which would not really be considered portable, there are some table top units which are more portable but do have restrictions on the load they can carry and their accuracy for long exposures, aiming for say 3 Min exposures would be a good starting point, have a look at the following for an idea:-

SkyWatcher Merlin SynScan Goto AZ Tabletop Mount

and

http://firstlightoptics.com/products.php?cat=46&pg=4

SkyWatcher EQ1 Tabletop Mount & Drive

I have just linked to these ones as an example as they will be available from many sources. Give FLO, the forum sponsors (link at top of page) to discuss your options as they are many and varied.

Brendan

[pvaz]

To me that astrotrack package deal seams a good buy, if you don't already have a good tripod and head. It actually comes with 2 heads. All of those extras can be used on regular, everyday photography and being from Manfrotto quality is assured. (I don't have the astrotrack but I do have a Manfrotto tripod and ball head which are great.)

[jgs001]

One thing to bear in mind, with the Merlin mount, as it's AltAz you're maximum exposure time is of the order of 2 minutes when low in the east or west. This is, apparently independent of focal length but I've never tested that. For exposures of the order you are talking of, you need a very well setup mount or a guiding rig. The guiding rig can get expensive, awkward and involves far more than just a camera. Having said that, with the Siggy 50mm, even 2 or 3 minute exposures is going to suck in a huge amount of light.

Portability, I don't know if the little eq1 would give you the tracking accuracy for long exposures, it's pretty lightweight as eq mounts go, although again if that Siggy is small and light..

The Astrotrac, from the images I've seen and the information I've read seems to be the ideal setup for portable camera/lens based imaging.

None of these has goto. If you want goto as well, in the cheap price range you're looking at something like the Merlin, or the Skywatcher Az, or something like Skywatcher - Skywatcher EQ3 PRO Synscan GOTO. I don't know the mount, but it would probably be sufficient to bear the camera and lens for imaging. Whether that would be classed as portable... that would depend on how you were getting where you were going.

Give Steve at FLO a call.

[brendant]

Meeting the requirements of long exposure / portability and GOTO is a really difficult, the Astrotrac is ideal for long exposures as it has superb tracking ability provided it is accurately polar aligned and also fits the bill for portability but not GOTO.

The Merlin has GOTO but being ALT/AZ in not good for long exposure over a couple of minutes but is reasonably portable and has GOTO.

The EQ3 Pro fits the bill for tracking for 2-3 mins but would require guiding for 5 min exposures, portability is questionable but the requirement for GOTO is satisfied.

An equatorial mount or Astrotrac are the only mounts that will allow 5 Min + exposures provided they are accurately polar aligned. An interesting requirment so will be interested in the outcome.

Brendan

[Loogie]

How about this one ? I guess it doesn't have to be super portable. We are talking about throwing it in the luggage hold on the plane. The camera doesn't leave my hands.

SkyWatcher SynScan Goto AZ Mount & Tripod

The merlin looks a bit flimsy to put on the ground..

I take it that a "standard Sky-Watcher/Vixen dovetail bar fitting"

means I can screw my camera/ lens directly to it. Or do I need some fancy converter ?

[pvaz]

Az mounts move in zig zag so some trails will be visible with that one, when using long exposures. You need a motorized german equatorial mount (EQ or GEM for short) for long exposures. This mounts move in a circular path at the same rate as the earth but opposite direction, canceling the apparent movement of the stars/objects.

The goto is optional for photography the EQ mount isn't if you want long exposures (1/2min+). I would probably look for a Skywatcher eq3 or an EQ5. The PRO version of both is motorized and haves goto. They aren't very portable.

Skywatcher - Skywatcher EQ3 PRO Synscan GOTO

Skywatcher - Skywatcher EQ5 PRO Synscan GOTO

This 2 require an external power pack.

The Astrotrack is probably the most portable you can get as it's not as heavy and seams to work on bateries, but you'll have to pass on the goto... It's a hard choice, nothing seams to fit the bill completely.

EDIT: Maybe you can pick some old binos you may have at home, then get this free monthly map and learn the sky a bit so you won't need goto. It's easier then you may think!

[Merlin66]

What about a s/h ETX with a piggy back adaptor??

It can be set up as an Equatorial and has the GOTO capabilities???

WPO - Meade ETX-70AT with Autostar

[brendant]

Yes this means with your camera/lens screwed to a standard dovetail bar you will be able to be removed quickly similar to a tripod quick release clamp, removal is usually by two hand tightened clamp knobs.

The requirement for 5+ Min exposures is very demanding, as none of the mounts mentioned so far are capable of this out of the box, EQ3 Pro / EQ5 Pro are not capable of guiding without trailing over this period of time, I have an EQ5 Pro and a HEQ5 Pro and have to use guiding (requires second telescope/lens - guide camers + computer) to get 5 Min exposures - up to 3 Mins is possible out of the box. THe only mounts capable are extremely expensive - top of the range (£1K++) and not in any way portable as in hand luggage.

The astrotrac is capable only if set up absolutely correctly and then I would assume only with relatively short focal lengths up to say 200mm. (Hopefully someome who has one will reply - may be worth starting another thread asking for peoples experiences of using the Astrotrac).

Brendan

[Loogie]

I don't like the sound of "Az mounts move in zig zag "..... if it isn't sharp in the first place it will end up in the trash..

OK the reason why I want a goto is that my 150 mm and 300 mm lens (both F2.8) isn't easy to see stars through... So hunting around for obscure objects through a lens I can't see just seems like a bad deal to me. At least with goto I can just preset the focus and fire away for a few minutes. With the 5D Mark II I can push the ISO pretty high so I should get some decent stuff through that.

As for 5 minutes.. that was just a number I picked. I see a number of good shots taken with less than that. If you can take good nebula shots with 30 seconds * 50 exposures... I'm more than happy with that.

[Merlin66]

Alt Az don't actually move in zig-zags- they are very smooth in the movements, but only accurately track on a point image in the centre of the field of view, this unfortunately gives field rotation across the image. This limits the useful exposure times etc.

A polar mounted tracker is the way to go.

[jgs001]

In Alt Az, you should be able to get exposures of at least 30 seconds. Many Many of them will get you results. You can get up to 2 minutes low in the east or west... The difficulty is always going to be, that some targets are likely to require longer exposures and large numbers of subs, and that will get very frustrating. At that point you may well regret the AltAz mount, and investing in an EQ mount that can handle the load of the kit you want to mount, with the ability to add guiding later will make more sense... they tend to be more expensive and heavier though.

[Loogie]

When you say "guiding"... do you mean goto...

[Merlin66]

No guiding is an "extra" issue/ problem/ $$$$ were a separate telescope fitted with a separate guide camera is mounted along side your imaging camera/ lens to "lock on" to a field star and send signals to the drive on the mount to compensate for any errors in the tracking drive.

Nothing to do with GOTO, which just drives the telescope/ camera to a nominated position in the sky then reverts to siderial tracking.

Hope this helps,

Ken

[jgs001]

Guiding allows for much longer exposures, but as Ken pointed out it's a lot of extra components, and potential for issues/problems/frustrations. And if you think you might want to go there... it'd be well worth getting a mount that can do it now rather then buying one now and deciding in a few months that you really wanted to be able to do that ...

[brendant]

Here is a link to a useful site which discusses astroimaging with DSLR's and lenses, Lenses for Astrophotography, some very good info on this website and worth browsing, Jerry Lodriguss is a very experienced imager, site also contains info on the processing of astroimages.

Here is a link to a site which discusses the 5D MkII and its spectral response for astrophotography - EOS40D / EOS50D comparison (don't mind the heading the 5D MkII is included in the review)

Hope this info is of use.

Brendan

[Loogie]

I got the Merlin in the end. But I'm struggeling with the tracking.

I calibratd it ok. I type in a star and the handset finds it for me... It says slewing for about 30 seconds after it finds it which I guess it is it's way of tracking...

And then it stops.... But I want it to track for more than 30 seconds ? How do I just do tracking ? I see there are options for slew speeds... 1 to 9... which is needed for stars ?.. also in the tracking setup I can chose lunar, sun and so on. Obviously I didn't pick those.

Any help appriciated !. I'm in Norway in the mountains and visibility is perfect.. but I'm gutted I can't get some decent tracking