Ha filter on DSLR

[johnrt]

Does anybody use a Ha fiter on their dslr?

Would it be worth it?

I'm imaging the process may go something like stacking Ha subs, stacking rgb subs then combining.

Would this give better results?

I use a Baader MPCC which takes 2" filters on the end so would be a simple thing to add in to the imaging chain.

Questions questions!

John.

[Psychobilly]

I have used a 2" 30nm one on my modded cameras...

Peter...

[davew]

Hi John,

As Peter says, ok on modded DSLRs. Non modded only allow about 10% ( ish ) of Ha info to get through. Even worse with S11. This info is found on modding sites that give before and after graphs.

I don't think inverse square laws apply so we're maybe looking at 30 minute exposures !! Someone may have more good info than this.

Nice thought.

Dave

[johnrt]

I have a modded 1000d so no problem there.

What kind of results did you get Peter? Is it something worth trying? Or was there no significant difference overall.

[Psychobilly]

Sorry I went to grab some ugly sleep i'll dig out some "mono" subs and post them...

Or i'll serach out the threads from last year and post the links... I had deleted the attachments as I had run out of space in the threads so I have found these two for starters...

It's the Baader 35nm 2" filter that I used on a BCF modified 1000D on the front of the FFFIII in the Mergez 72.. I probably still had the Hutech IDAS P2 on as well.. that tends to be left in place...

Here's the first... will have to dig out the exposure details...

I know this is 25x900s ...

Peter...

[johnrt]

Peter, they are excellent results, better than I thought was possible. I wonder why more dslr users don't seem to try this?

[cardconvict]

did you set your dslr to mono to shoot these ?

[Psychobilly]

did you set your dslr to mono to shoot these ?

No They are converted to Mono in the post processing...

Peter...

[cardconvict]

sorry this is all new to me, i have a c9.25 canon 450d mod at prime focus if i went to buy a ha filter how would i attach it, or could you buy a clip on which is expensive, like all the clip on filters

[angusb1]

Hi John,

As Peter says, ok on modded DSLRs. Non modded only allow about 10% ( ish ) of Ha info to get through. Even worse with S11. This info is found on modding sites that give before and after graphs.

I don't think inverse square laws apply so we're maybe looking at 30 minute exposures !! Someone may have more good info than this.

Nice thought.

Dave

Sorry if this is OT or if I have misunderstood but don't the unmodded Canons allow around 25% Ha through their filter? I read it here.

[Psychobilly]

Ha transmission depends on the model... the newer cams are better than the older ones.. which is why you can do more with them "un-modded" than you could with the older ones...

[johnrt]

I invested in a Ha clip filter for modded my 1000d - I have never tried to use it on an unmodded camera but would speculate that it blocks so much light you would get virtually nothing.

The bayer matrix on a dslr is RGGB so only 25% of the pixels are collecting data when using a Ha filter even with modded cam.

Not had much time to use this filter yet but I did manage to collect 8 10min subs the other night.

[Psychobilly]

Which clip in filter did you go for John.. ?

Nice Data

Peter...

[johnrt]

Thank you!

I went for the Astronomik 12nm from Bern. Top service as usual.

[cardconvict]

ok cool

[MickyWay]

I have used a 2" 30nm one on my modded cameras...

Peter...

Hi Peter,

I'm impressed with the results you get with a relatively wide (30nm) spectrum. What's your thoughts on the 12nm Ha filter?

Any advantages, apart from cost?

[Psychobilly]

The 12nm would give more contrast... the 2" 30nm came courtesy of SAN mag for a Crescent Nebula Widefield image...

[MickyWay]

Not a bad freebee then!

How do you find focusing through one of these filters?

[Psychobilly]

I use a Bahtinov and its not too bad... you get dashed rather than solid lines but the principle stays the same... need longer focus exposures than normal as well...

Peter...

[MickyWay]

Thanks Peter,

I think I'll go for the 12nm......... unless I can win POW with S @ N ........mmmm

[Psychobilly]

Thanks Peter,

I think I'll go for the 12nm......... unless I can win POW with S @ N ........mmmm

There's a new company providing the prizes these days... although I did Call in to TP to collect mine in person...

I did use the 30nm on fairly moon washed nights and it produced reasonable results the 12nm should be quite a bit better...

Peter...

[Russe]

So, until and unless I mod my Canon450d I should forget about Ha, SII or OIII?!

[ollypenrice]

I can't see that modding will have much effect on O111 or S11. O111 has certainly been done with DSLRs but the imagers describe it as agonizingly slow. (I find this odd because there are two green pixels per cluster of four and really the blue ought to pick up a bit as well. Can anyone explain this?)

Olly

[Kbramley]

I found SII was very difficult still even with my modded 450D and 2" SII filter, however Ha was vastly improved over an umodded camera as one would expect, especially as there are plenty of targets out there with strong Ha emissions.

[Russe]

How can you attach filters to a DSLR if you need a coma corrector and have very little distance left for spacing with a Newtonian?