Pardon my ignorance but I am extremely confused

[InkRule]

Hi, im Andrew and I guess im extremely new to astrophotography, only thing i ever took a photo of was the moon and that's what got me really interested in astronomy.

Hence, I went on to modify my Canon 50d into a full spectrum camera. Sadly I haven't found clear skies or places with the least light pollution to take pictures of the stars. Then today I chanced upon this forum and realized that filters are needed, broadband, narrowband and H Alpha filters. Im wondering which would I need to usage in Singapore(Light pollution in mind) If there was one filter I would have to get for my 70-200mm f4 non-IS lens, what would it be? Im extremely confused. Orion Ultrablock is for telescopes right? Ughhh too much confusion, as much as i would like to join the Mersing trip on the 12th, i fear i would not be able to take any pictures with my lack of equipment.

Thanks for any patient replies and understanding, I have much to learn from all you seniors

[Mariner]

You dun need filters for basic AP unless you intend to do very long exposures. Alot of visual filters are not suitable for AP use as they transmit less light than those specially designed for AP and CCD.

For visual, the selection are broadband (LPR), narrowband (UHC, NPB) and line filters (O-III, H-beta) and a selection of colour filters.

You dun need much equipment to take AP. A camera and a sturdy tripod would be the minimum. Just ask rcj and gang.

[Gary]

Hi Andrew. Welcome to the forum!

I am not an expert in astrophotography, so I will let the experts here answer your filter queries.

Regarding your confusion, just wanna say be patient and enjoy the learning process! Clear skies in Singapore will come sooner or later. Read up about the subject matter as much as you can during cloudy nights.

The best way to learn is from the experts in this forum in person and practice your astrophotography with them in Singapore or overseas. Don't need to feel embarrassed about not knowing enough about the subject matter. We all were complete beginners once upon a time.

In case you have not come across this website, check this out whenever you need motivation to learn more about nightscape astrophotography: http://www.twanight.org

Good luck and have fun!

[cloud_cover]

Welcome to the world of Deep-Sky Astrophotography! Also, congratulations on your spectrum-enhanced Canon
First off, do you have an tracking equatorial mount? You'll need one of those in order to track the stars for long-exposure photography. Examples of this are the Celestron CG-5/CGEM, Orion Sirius/Atlas/EQ6, Vixen GP or SX series to the higher end Losmandy G8/11, Astro-physics or Paramount mounts. If you don't have these, you can still do astrophotography but you'll need to use short focal lengths and keep your exposures short. (e.g. 20s exposures at 50mm)
If you're going up to Mersing, you can do without filters as the sky is reasonably dark although if you're exposing longer shots, filters will be helpful. A note though: the function of a filter is to let through wavelengths of light that are commonly associated with astronomical objects, and block other wavelengths that are associated with light pollution. As such, filters work best when the target emits specific wavelengths of light that are separate from light pollution. A good example of this is the Hydrogen-Alpha line, which is emitted primarily from emission nebula, caused by excited hydrogen atoms (hydrogen being the most abundant element in the universe). Conversely, filters don't work so well when imaging "broadband" targets, such as star clusters or galaxies as they give off light that spans the whole spectrum, hence using a filter that cuts down the wavelengths of light commonly associated with light pollution also cuts down part of the light emitted by these targets. As a broad rule, filters are most effective on emission nebulae, such as the Orion Nebula and the Lagoon Nebula, to name 2 famous objects.
If you're going to get a filter, then a narrowband filter such as a UHC filter will be the most useful. Since you're using a camera lens, the usual astronomical sizes will not be usable so your best bet is to obtain a clip-in filter such as the Astronomik UHC Clip In filter for Canon EOS or the IDAS LPS-V4. Other narrowband filters such as the HA/OIII/SII filters are less useful in a color DSLR (even a spectrum enhanced one) because a lot of the light coming through the filter does not reach the CCD sensor thanks to the color bayer matrix directly in front of your CCD sensor. These filters are more useful in astro-dedicated mono cameras.
Hope it helps!

[weixing]

Hi,

Hi, im Andrew and I guess im extremely new to astrophotography, only thing i ever took a photo of was the moon and that's what got me really interested in astronomy.

Hence, I went on to modify my Canon 50d into a full spectrum camera. Sadly I haven't found clear skies or places with the least light pollution to take pictures of the stars. Then today I chanced upon this forum and realized that filters are needed, broadband, narrowband and H Alpha filters. Im wondering which would I need to usage in Singapore(Light pollution in mind) If there was one filter I would have to get for my 70-200mm f4 non-IS lens, what would it be? Im extremely confused. Orion Ultrablock is for telescopes right? Ughhh too much confusion, as much as i would like to join the Mersing trip on the 12th, i fear i would not be able to take any pictures with my lack of equipment.

Thanks for any patient replies and understanding, I have much to learn from all you seniors

I notice that you mention that you mod your Canon 50D to a full spectrum camera, in that case, you'll need at least an IR blocking filter or filters that had IR blocking built-in if you are using a refractive system (such as APO(or ED) Refractor, your 70-200mm F4L & etc), so do check the filters description before you purchase one.

Anyway, you'll need a decent EQ mount with at least a RA motor drive to compensate earth rotation for long exposure.

By the way, where you mod your full spectrum 50d and how much does it cost?

Welcome to SingAstro and have a nice day.

[InkRule]

@Mariner - I see i see, i see a website selling H- Alpha filter, i was thinking of getting that. Will join on the next outting to learn more

@Gary - Thanks for your warm welcome The website was a sweet touch, thanks!

@cloud_cover You were the reason I took over a week to reply hahaha, thank you soo much for spending a lot of time to reply me with a very detailed post
I do not have a tracking equatorial mount, would i really have to use exposures that long? I thought i could get pictures of stars rather easily. I missed the Mersing trip due to work commitments, quite sad actually, i anticipate joining the next group outting. So i guess I'll be getting a H-Alpha filter from
http://www.spencerscamera.com/store/sto ... gory_ID=39
hopefully they are a good website.

@weixing Hi! I modded my Canon 50d to full spectrum at Camera Hospital at Sun plaza, selegie. However his mods do not include another clear glass to replace the preexisting IR blocking filter, which means i have to be much more careful with my sensor, I modded it for about.. $200 Sgd i think, not even sure if it was a good deal lol. The only IR filter i have is from Hoya, the completely black one.
But a refractive system?? I have no idea what that is.

Thank you all soo much for the warm welcome into the forums

[InkRule]

Sorry wrong link!

http://www.spencerscamera.com/store/sto ... gory_ID=21

[weixing]

Hi,

@cloud_cover You were the reason I took over a week to reply hahaha, thank you soo much for spending a lot of time to reply me with a very detailed post
I do not have a tracking equatorial mount, would i really have to use exposures that long? I thought i could get pictures of stars rather easily. I missed the Mersing trip due to work commitments, quite sad actually, i anticipate joining the next group outting. So i guess I'll be getting a H-Alpha filter from
http://www.spencerscamera.com/store/sto ... gory_ID=39
hopefully they are a good website.

Are you going to use your EF 70-200mm F4L? If yes, you'll need to use an EQ(equatorial) mount unless you don't mind taking star trails (star trail will appear quite fast due to your focal length) instead of pin-point stars. Anyway, please note the H-Alpha filters in your link are for telescope use... 2inch (50.4mm) and 1.25 inch (31.75mm)... your EF 70-200mm F4L use 67mm filters, so not suitable and 67mm H-Alpha filter are very expensive and I think require custom order. Since you are using Canon 50D, you should use those clip-filters that install in your DSLR, so it's a lot smaller and cheaper. Check out this website (you can order from other dealer such as OPT):
Clip Filter for EOS Camera: http://www.astronomik.com/en/clip-filter-system.html
H-Alpha Filters: http://www.astronomik.com/en/photograph ... ilter.html

@weixing Hi! I modded my Canon 50d to full spectrum at Camera Hospital at Sun plaza, selegie. However his mods do not include another clear glass to replace the preexisting IR blocking filter, which means i have to be much more careful with my sensor, I modded it for about.. $200 Sgd i think, not even sure if it was a good deal lol. The only IR filter i have is from Hoya, the completely black one.
But a refractive system?? I have no idea what that is.

Thank you all soo much for the warm welcome into the forums

The Hoya IR filter is an IR-pass filters (let IR go through and block the rest... that's why it look black) for IR photography... what you need is those IR blocking (block IR and let the rest through) filter. Most CCD astro-imaging filters will have IR blocking built-in, but better check the specs before you order.
A refractive system is a telescope or lens that use only lens (no mirror)... When light passing through a lens, IR light do not come to the same focus point that normal visual light do and that will cause bloating of star images... that's why you need IR blocking filter for refractive system.

Have a nice day.

[Davegn]

Hi InkRule and weixing,

just sharing with you the image i took of the milky way last year with an Modded D70S (IR Hoya R72).


6x15Mins. Light frames only.
custom white balancing,
Red and Blue color channel Swapped

[Gary]

Wooo! Nice Milky Way!