Filter recommendations for someone starting out

[Tenor Viol]

I'm pulling together my first AP rig. I've got the mount (HEQ5) and I've bought a secondhand astro-modified Canon 700D (I don't want to modify my main Nikon cameras). I will shortly be ordering an 80 or 100mm APO triplet of some description... So, coming to the question of filter requirements to improve images. 

I live in a market town in north Shropshire, population 9k. The map says I have a Bortle class of 4. I'm on the edge of town. No major towns for about 15 miles. Local lighting is mostly orange low pressure sodium with a few LEDs. The local leisure centre has outdoor pitches with mercury vapour flood lamps - that's about 2 miles away. Good news is most (not all) street lights get turned off around 11.30pm.

That's the background... I've been digging around and it would seem that a likely contender for a suitable filter to use is the CLS-CCD. There are several flavour of this with SkyTech coming in around £90 and Astronomik coming in around £140. The cheaper one seems to add some red colour cast, not sure if the Astronomik does as well. Similarly some haloes around stars seem to be the case with the cheaper one. 

Is this the right sort of filter I should be thinking about and if so, is the more expensive one the way to go? 

[Adam J]

33 minutes ago, Tenor Viol said:

I'm pulling together my first AP rig. I've got the mount (HEQ5) and I've bought a secondhand astro-modified Canon 700D (I don't want to modify my main Nikon cameras). I will shortly be ordering an 80 or 100mm APO triplet of some description... So, coming to the question of filter requirements to improve images. 

I live in a market town in north Shropshire, population 9k. The map says I have a Bortle class of 4. I'm on the edge of town. No major towns for about 15 miles. Local lighting is mostly orange low pressure sodium with a few LEDs. The local leisure centre has outdoor pitches with mercury vapour flood lamps - that's about 2 miles away. Good news is most (not all) street lights get turned off around 11.30pm.

That's the background... I've been digging around and it would seem that a likely contender for a suitable filter to use is the CLS-CCD. There are several flavour of this with SkyTech coming in around £90 and Astronomik coming in around £140. The cheaper one seems to add some red colour cast, not sure if the Astronomik does as well. Similarly some haloes around stars seem to be the case with the cheaper one. 

Is this the right sort of filter I should be thinking about and if so, is the more expensive one the way to go? 

To be honest I would not go with a CLS CCD from Class 4 skys its too harsh and compromises colour balance.

Class 4 is actually quite good by modern standards. I would even give galaxies a try with no filter especially if your local lighting is LED, although the sodium light might cause an issue I would imagin they will soon be replaced so it might not make too much sense to buy something to mitigate them in the short term. I dont use a filter for galaxy imaging from my class 5 site. 

For emission nebula I would pick up one of these:

https://www.firstlightoptics.com/optolong-filters/optolong-l-enhance-dual-narrowband-deep-sky-imaging-filter.html

I would go with 2 inch filter if it was me as that will allow you to keep using it if you ever change to a cooled OSC camera.

Adam

Edited June 3, 2020 by Adam J