IR filters

[Neil H]

Hi all I have a ASL 224 MC  camera I ordered the wrong IR filter I got a pass not a cut , the guy at the telescope house said that this filter is better for planets when they are low as they are now and a cut filter will be better when they are high up , so I ordered a IR cut filter so I have both now my questions are 

Do you ever use a IR pass filter ? What sort of photo will you get ?

will it be better on planets low in the sky ?

this is the email I got 

Hi Neil,

 

Apologies you haven't heard back from us - we are incredibly busy currently.  Unfortunately the order has actually gone out already.  You're welcome to return the filter if you want.

 

The filter you've bought actually matches the 224 extremely well.  While it’s not a conventional IR filter and we can certainly swap it over for one if you want to return it, I would actually recommend sticking with this filter as well - it’s veryuseful and will allow you to do a lot more with the camera, especially during the permanent astronomical twilight we're experiencing in the UK for the next couple of months.  This filter allows you to use the full resolution of the camera for IR and near IR imaging.  This is really useful when trying to combat poor seeing conditions you get when imaging planets lower down towards the horizon - ideal for where Jupiter and Saturn are currently located in the sky.  While a conventional IR filter like this one:

 

https://www.telescopehouse.com/accessories/filters/imaging/ir-cut-filter-1-25.html

 

will certainly help to tighten things up a little when dealing with brighter targets, it does depend what design of telescope you’re using as to the efficacy of using a fairly gentle low pass filter like this - what's your main telescope?

 

 

 

[CraigT82]

Which IR pass filter did they send you? 

IR pass filters are very useful for imaging the planets and the moon as the longer wavelength is less affected by atmospheric seeing. It's common to take a normal RGB image of, say, Jupiter and to use an IR image as a luminance channel (or as a replacement for the red channel) to sharpen up the details.

Also imaging the moon in poor seeing through an IR filter can yield good results. The IR filter can also be used to darken the sky and increase contrast on the moon when imaging in a blue sky.

The RGB bayer matrix filters on the camera you have all let IR light through equally, or thereabouts, allowing the camera to operate as a mono camera would, with all pixels receiving the IR light. 

[Neil H]

It is not here yet but email said 850mn  if that means any thing to you Craig

[CraigT82]

OK thats the ZWO 850nm longpass filter. Probably not as useful as an Astronomik 742nm bandpass or the Baader 685nm longpass, but you could still give it a go and see what you think of it.

[Neil H]

Ok will do i will have loads of questions  like what are darks ? What are flats ?

[CraigT82]

5 minutes ago, Neil H said:

Ok will do i will have loads of questions  like what are darks ? What are flats ?

Haha I only do lunar/planetary I've no idea... sorry!

[Neil H]

Ok Craig that focuser i got from you is so nice to use made the telescope  so much better  . I will come to you when i get stuck on the planets