Imaging session Jan 2009

[Carole]

Can I double check this is on Thursday 29th?

Mike, if it is cloudy can I request some tuition on use of filters and adding colour to B&W images.  I am thinking about taking the next step and getting my webcam modified which will then make it B&W and would like to know how to put colour back into the image.

Thanks

Carole

[Mike]

You can only 'add' colour if you have captured colour data using filters.

Sure I can talk about filters no problem.

[Carole]

You can only 'add' colour if you have captured colour data using filters.

Aha, lesson number 1.

So I need to buy filters as well, would it be the gadget you showed at the Imaging session which was a sort of wheel that rotated with various filters which cost £250?
Could you buy the filters individually rather than use the wheel, obviously this is fiddly, but might be cheaper?
You can answer that at the Imaging session if you like.

Carole

[Mike]

A wheel is from £50 upwards and filter sets are usually around £80 upwards. A wheel is essential unless you have a rock solid mount as you will upset the image train. You could only not use  wheel if you were guaranteed to take the imaging kit apart, put in your new filter and put it back inexactly the same place without moving your mount at all. Unless you have an AP1200 or a paramount that is not going to happen.

There are cheaper options such as filter slides which allow one filter at a time to be slid into the imaging train. Speak to Bern at Modern Astronomy he will advise you best on what you need and he is usually the cheapest (if you tell him you can find an item cheaper elsewhere he will usualy match or beat the price too).

[JohnP]

Carole if you are going to get into monochrome imaging & get filter sets then you definitely need a filter wheel - you will drive your self crazy if you don't have one.... believe me I've played around with manually swapping filters & it's a nightmare... If you get something like Astronomik Type II they are parfocal which means you do not have to refocus when you go to a different filter. I picked my LRGB Astronomik type II set up from Astrofest for about £125 CASH deal though - this was a big saving over the then list price...

John

[Carole]

This sounds like another page to add to my FAVOURITES. 

John, when you said cash, I assume you mean hard money as opposed to cards or cheques.  I am planning to go to Astrofest, so will see if I can find something.

I understand what you are all saying and it seems sense to get a wheel. 

Carole

[JohnP]

yep hard money - there is a cashpoint just around the corner...it's where I went to get mine out....

[Carole]

there is a cashpoint just around the corner

Good tip, I am not normally a cash person, as I never know how much I am going to need.

Carole

[mickw]

Carole,
It will always be more than you've got - if that helps 

[Carole]

Before I go buying filter sets, I do have a LP filter which is labelled Ultrablock TM Narrowband 1.25".  When I use this everything appears green.

I am just checking that I haven't already got one of the filters that I need.
I guess it probably isn't but it is the green aspect that is giving me some doubt.

I have written this all in the negative. 
Therefore. 

Have I already got one of the filters I need for a filter wheel?

Thanks
Carole

[Ian]

you might. It depends what filters you want to put in your filter wheel. You've got a colour camera, and so with a small number of exceptions, filters are not going to be hugely useful. Have you tried with the one you have? Without looking it up, I suspect it's a narrowband light pollution rejection filter, and the green cast may process out. You'll probably need to stack it with an IR filter as well, which you should already have.

Once you go to a mono camera, then filters are absolutely essential if you want any colour image of any sort. If someone's going to talk about at Mike's this week, I'd listen to that primer first, then have a think about what sort of imaging you're planning on doing and then think about filters. They can be extremely expensive so you need to know exactly what you want (unless you're really rich )

[Carole]

Hi Ian,

I think you might have missed a previous bit of conversation I had with Mike in this thread, as I am thinking of having my webcam modified making it B&W so I can do some basic deep sky stuff and so will need a filter wheel to put back colour into the images.  (Yes I know I still have the ETX but Rome wasn't built in a day and I have to do this in stages, both financially and from a staged learning point of view), I know that you can do some limited deep sky stuff with an ETX.

Was just checking whether the LPR (green) filter I have might be one I would need for the filter wheel.

Can some-one tell me how many filters I will need and what they are.

I already have the one stated:
Ultrablock TM Narrowband 1.25" (green)
IR filter

I have heard others talking about Ha filters.

It depends what filters you want to put in your filter wheel

I just want to put back the colour that one might get using a colour camera.

Hope this makes sense.

Carole

[Mike]

In which case you need an LRGB set.

[Carole]

Thanks Mike.

I'll ask any further questions at the Imaging session.

Carole

[Ian]

fair enough. I would explore the possibility of buying a dedicated mono camera rather than getting your webcam modified for mono. Just an opinion based on having had both...