Astronomik, Canon and astro-imaging. Anyone tried Clip-Filters ?

[mickyj]

Hello,

I am almost a complete Newbie to Astrophotography. My skills are limited to High ISO 30 sec shots of the Milky way and 1 hour shots at low ISO of the stars at the horizen, using the Southern Cross to pinpoint the center of the star trails.

I have an el-cheapo Telescope and a T adaptor that does not fit

Up until now I have used my canon 5D and 70-200 mm for star shots. I have seen some really cool shots using hydrogen-alpha solar filters and was looking at maybe getting a Clip-Filter (EOS) with ASTRONOMIK H-Alpha-CCD 12nm, for my Canon 7D.

Has anyone used these on Canon and can give pointers? Can anyone give any pointers on starting with Astrophotography with a very small budget ?

[ameerat42]

Ha-ha Mickyj. I guess "Don't start with H-alpha filters." would keep the costs down. I've been looking at them myself, recently, and they do cost.
Even the small broader band ones for the front of eyepieces are expensive.

Of the shots you've seen on AP, I would doubt that any H-alpha filters were used. People mostly stack frames to produce either trails or detailed starfields.

What is your el-cheapo scope, and I'd be interested to know why the T-adapter doesn't fit.
Am.

Edit: (Forgot in my haste) Do you have an equatorial mount to track stars? I had a look at some of your gear. Wide aperture glass is essential for good star shots. At least an inch (2.5 cm) of clear aperture used to be the rule-of-thumb.

[mickyj]

Thanks for the reply. I have read that the IR Cut off filter in the Canon Camera's should be removed for the best results with H-alpha but I am reading on the Astronomik website that their clip filters do not need you to do this. That is one of the reasons I wanted to throw the question out there and hoped someone might have tried it

Yes, the h-alpha for filters that fit to the end of the lenses, are very expensive. The Clip units go into the throat of the camera, before the lens (only for EF lenses and only certain Canon Camera's) and are cheaper (But still not cheap).

Before I take the plunge, I want to be sure my expectations are set.

I have looked at stacking programs and am interested but I think I need to start with better images first.

The Elcheapo was purchased for my Daughter from eBay. Literally a cheapie. It was called a "ASTRONOMICAL & TERRESTRIAL 525x ZOOM TELESCOPE". It came with Barlow lenses etc but the hole at the end of the telescope is not a normal diameter.

[ameerat42]

Yes, such things have been around for ages, but I'm sure your daughter meant well.
They sport a modest mirror of about 4.5 inches, a focal length of about 900mm, and they give you a 12mm or so eyepiece and a barlow.
If it's a reflector, you might be fortunate in having a light duty equatorial mount. The refractors usually sport just a flimsy fork-design alt-azimuth mount.
Often, though the main mirror or objective lens is quite passable, and some firming up of the mount can make the whole thing moderately useable for some observing.

I'm sure they're designed to put people off astronomy.

Your camera lenses would be the go for serious photography.
Am.

[mickyj]

Well, it looks like you (Am) and me learning together on this one, One of us will be starting down the h-alpha road sooner or later

[ameerat42]

Well, it looks like you (Am) and me learning together on this one, One of us will be starting down the h-alpha road sooner or later

Well, it would be interesting to try, especially for solar views. But I think before that I will have to expend some effort and money on getting the makings of a 12-inch reflector back into a telescope form.

I've had it like that since I bought it (decades ago). It looked so promising and inviting when I pulled it out again today during a tidy-up. I briefly mentioned it in another (recently revived old) thread.

Do you know there's an interesting tutorial here on AP about astrophotography: http://www.ausphotography.net.au/for...trophotography

Am.

[mickyj]

Excellent. I am reading that post right now.

[SteveInNZ]

I think you may be confusing H-alpha filters for solar imaging and H-alpha filters for deep-sky. They are completely different animals.
A deep-sky filter (of which the clip-in is an example) has a bandwidth of around 5-15nm and lives at the camera end of the imaging train. It is designed to pass the light emitted by H-alpha in a dark background.
The solar H-alpha filter (system) consists of two parts and has an extremely narrow bandwidth (<0.1nm) and is generally a dedicated telescope.

As you have seen, it's quite common to replace the IR filter in the camera. Different cameras have different levels of response to Ha. Some DSLRs might be a stop or two down but some like the 5D2 seem to really knock it out. If your camera isn't sensitive to Ha, adding an Ha filter isn't going to help. However, if you live in a region with lots of light pollution, a Light Pollution filter (LP or CLS) will help a lot as it blocks streetlight wavelengths and passes astronomical wavelengths of interest so you can expose for longer before the background washes out your subject. You can buy those as either eyepiece filters or clip-in filters.

Of far more importance in astrophotography is the mount. Where every other forum will say "spend your money on good glass", here it's all about the mount. Any form of equatorial mount will open up a universe (pun intended) of possibilities. That can be as simple as a homemade barndoor tracker upwards. Then it becomes a case of staying within the capabilities of the mount.

Steve.

[ameerat42]

I think you may be confusing H-alpha filters for solar imaging and H-alpha filters for deep-sky. They are completely different animals.
A deep-sky filter (of which the clip-in is an example) has a bandwidth of around 5-15nm and lives at the camera end of the imaging train. It is designed to pass the light emitted by H-alpha in a dark background.
The solar H-alpha filter (system) consists of two parts and has an extremely narrow bandwidth (<0.1nm) and is generally a dedicated telescope.

As you have seen, it's quite common to replace the IR filter in the camera. Different cameras have different levels of response to Ha. Some DSLRs might be a stop or two down but some like the 5D2 seem to really knock it out. If your camera isn't sensitive to Ha, adding an Ha filter isn't going to help. However, if you live in a region with lots of light pollution, a Light Pollution filter (LP or CLS) will help a lot as it blocks streetlight wavelengths and passes astronomical wavelengths of interest so you can expose for longer before the background washes out your subject. You can buy those as either eyepiece filters or clip-in filters.

Of far more importance in astrophotography is the mount. Where every other forum will say "spend your money on good glass", here it's all about the mount. Any form of equatorial mount will open up a universe (pun intended) of possibilities. That can be as simple as a homemade barndoor tracker upwards. Then it becomes a case of staying within the capabilities of the mount.

Steve.

Good to see you here Steve, and I agree with your advice, esp the last paragraph..
Am.

[SteveInNZ]

Thanks Am. I've been patiently waiting for a thread where I understood what they were talking about.

[mickyj]

Thanks Steve. I actually want the H-Alpha for deep-sky and was hoping to try this in combination with some other filters I already have, for Solar. I am no expert on this so your advice is very welcome.

I am reading up on Barn door mounts as the Skywatcher units are beyond my budget

[SteveInNZ]

Barn door mounts are OK if you're good at woodwork and have a really solid tripod. I've tried a couple of times and never had much luck. You'd never guess it from reading on the net these days, but you can go a long way with a non-goto equatorial mount. It then comes down to how much effort you're prepared to put in to each exposure and polar alignment versus how much you save.
The bottom of the pile in equatorial mounts is the EQ-1. It's a skinny looking thing that you'll see on the cheapest scopes and I'd suggest avoiding that. The next step up is the EQ-3 sized mounts that you'll often see under short 6" reflectors. I think I paid $20 for one that someone had in their basement for years. The scope was stuffed, but I put a ballhead on the mount and used it like a barndoor mount. Take a 30 sec exposure, wind the knob a quarter turn, count to 5 and take the next exposure.
Next step up are used mounts like the Vixen Polaris, CG5 and EQ5 that have RA drives but no goto and no guiding. The CG5 and EQ5 are copies of the original Vixen design which is the best of that bunch. I picked up a used Polaris for about $250 and it will do 1-2 minute exposures without guiding at 1000mm focal length.

Before you buy the Ha filter, I would try and get to a dark site and do some test shots at some targets that are strong in Ha. eg. Orion nebula in summer and Eta Carina in winter. If your camera doesn't pick up the red, you'll be wasting your money on the filter because to get any benefit from it you'll need longer exposures which means more money on a mount.

[mickyj]

Thanks. I am trawling Gumteee and ebay for second hand cheap mounts. I have the dark site sorted and already had some fun with star photos. I just want to crank up the quality and difficulty and learn more

[ameerat42]

Thanks. I am trawling Gumteee and ebay for second hand cheap mounts. I have the dark site sorted and already had some fun with star photos. I just want to crank up the quality and difficulty and learn more

A good start, Micky. But do be careful of what you get. For serious astro stuff, which you seem to be heading for, a cheap mount might not be very suitable. Mounts are mainly - but by no means only - rated on weight-bearing capacity. But even so, some are so flimsily made that you couldn't really do anything with whatever weight you put on it.

Get yourself to an astro shop and try to have a look at some mounts. Get an idea of how they're made, etc., etc.

Anyway, you get the drift.
Am.

[SteveInNZ]

Yes, indeed. As I said earlier, the mount is _the_ most important part. Just to be clear, I'm advocating a cheap EQ mount is an alternative to a barn-door mount, not as the ultimate solution. It's the equivalent of trying macro photography with simple tubes or a diopter versus stepping straight into L glass.

[mickyj]

Has anyone got advice rearding a celestron nexstar-4-se. They seem to be camera friendly, reasonable aperture, motorised and affordable.

http://www.ozscopes.com.au/celestron...FUIkpQodYHcG1A

[ameerat42]

Mickey.

Who knows how relevant my info is, but here, it's free:
That's a slightly upscaled Celestron 90 of days of yore. The only one of those I had experience with gave terrible images at prime focus.

Lately I have tried using a Meade 90, looking something like this. I could not without buying a $100+ adapter for the camera - essentially a T-mount. I don't know whether Celestron include one.


Though maybe touted as camera friendly, they are not for these reasons:
1) they are very fiddly to use as they are
2) they would too shaky with a camera attached
3) the camera would interfere with the motions of the scope.

IMO, anyway. Their use is limited to just a small astro scope. And then, the "flip mirror" doesn't feel very accurate in its action, which in the Meade 90 at least, is spring loaded.

Am.

Oh - still had time to edit. Just looking @ the specs again I noticed that it comes with a "Sturdy" Alt-azimuth mount. That won't be as useful for tracking as an equatorial mount would be.
Also, there's no mention of a T-mount or any aid for photography, so there's an extra 100 bucks.

But wait, there's more: at least on the Meade 90, the finderscope was soooo ho-hum, and as for trying to align it with the main scope!!! Once "fairly near", it was easily knocked back out of alignment.
I don't know about the Cel finder.

[mickyj]

Thanks, this makes sence. I was looking at an eq3 pro but the $$$ scared me

[mickyj]

Taking everyone's advice into account I need to find:

An Eq mount/Tripod
Large Apperature Telescope
Goto computer control
Dark place
Canon EOS T adaptor

How about http://www.bintel.com.au/Telescopes/...oductview.aspx

EQ3 pro with Goto
150 mm Reflector

Any thoughts ?

[ameerat42]

Dunno, Mickey. I hesitate to give any advice as to a purchase. What you have shown is certainly not a bad looking/specified piece of kit.

Ultimately the Q is "What am I going/want/hope to do with it?"

If I am to say anything opinionated, it would be to be sure of what you want to do before taking any plunge. Sometimes - even with the likes of this - you may find that it is severely limited for what you might want to do or expect.

"Goto" is an interesting and potentially useful system, but if you don't align your scope properly, then I wonder where it will send you?

This is not a "Y" or "N" or any type of confirmation/advice against.
Am.