H Beta filter choice

[bomberbaz]

Hello all. I am considering buying a pair of 1.25 H Beta filters for my bins, my first proper outing with them has convinced me they will be of great use in finding objects that respond to this line of light well. EG california.

I have narrowed it down to the three below which are Blue line, Optolong; Turquoise line, astronomik and finally yellow tele vue. Price wise it is £68, £89 and £99 respectively. However I have now thought myself into a position of stalemate.

See chart below for bandpass information.

So the TV filter has the best bandpass and tightest filter by far. Then astronomik and optolong.  I am a little stuck on which way to go, highest quality is TV with ease.

So I have ruled Astronomik are out here as for the extra tenner TV is available. 

However optolong vs TV is difference of £62 for a pair of filters.

So my question is has anyone compared these two filters and what results were there?

I would expect there to be some minor difference but my suspicion is that it will be unlikely to be significant so I have to make the decision of high quality for very high quality.

So if any of you have comparisons or simply how they have found either of the filters (Optolong or Tele Vue) I would be very grateful.

Does anyone have any links to comparisons on other websites such as CNights? Doesn't have to be these filteres, just comparisons as this may help me past the current impasse and reach a decision.

Also if there are any filters in the £100 price bracket I have overlooked then again information would be useful.

FYI I have discounted ES H Beta, quite a slack bandpass and both cost and availability of Orion's version have left me to push them out of the equation too. 

Edited January 6, 2022 by bomberbaz

[rwilkey]

Hi Steve, have you considered Lumicon at all, I don't know the techy details but find my 2" version perfectly adequate.

[bomberbaz]

Thanks Robin. I have looked in the past and a quick look around shows them to be comparable to the astronomik in terms of h beta line pass and about as tight as the TV. However they are the same cost of the TV so just pipped by the TV.

What I did find were some Svbony h beta filters at only £49. However again bandpass lets it down at only 80% of the h beta line but how important is this likely to be. Opening thread edited.

 

 

[Louis D]

TV freely acknowledges that they partner with Astronomik for their Bandmate filters, if that makes a difference in your decision.

[John]

Personally I would try and go for something that has a 95%+ pass and quite a narrow pass width. I have the Astronomik H-B myself but bought that before the TV v2 Bandmates came out (also made by Astronomik as mentioned above).

The targets for H-B filters are challenging so I tend to think that every little bit of help you can get is worth having

A "fat" band width plus a sub-90% max pass seems unlikely to me to be a really effective line filter.

 

Edited January 6, 2022 by John

[Don Pensack]

10 hours ago, rwilkey said:

Hi Steve, have you considered Lumicon at all, I don't know the techy details but find my 2" version perfectly adequate.

Lumicon no longer makes an H-ß filter.

TeleVue or Astronomik, if available, are your best choice.  Just remember, this will be a low power filter.  If your focuser uses a 2" eyepiece,  don't buy a 1.25" filter.

You will be using this below 10x/inch of aperture, and 2" filters fit the bottoms of many 1.25" adapters so are usable on 1.25" eyepieces.

Edited January 7, 2022 by Don Pensack

[Permafrost]

Orion H-Beta, bang for the buck possibly.

[Don Pensack]

My Orion H-ß filter was a surprise--a 12nm bandwidth and a 94+% transmission.

It was a pain to thread in, and I had a couple others with even narrower bandwidths, so the Orion went.

But, given it is typically at a lower price than other high-end H-ß filters, it is certainly a good option.

[bomberbaz]

I keep revisiting this thread and wondering what to do, if indeed anything about this. 

Seeing as I am thinking of using with 82mm bins, equivalent to circa 100mm single aperture in comparison, some would say an HB filter is too aggressive to be an effective tool in these bins.

However I have also read threads in CN where these filters have been used effectively in far smaller apertures (30mm) so I am feeling somewhat bemused by this as it smashes the considered rule of thumb on filters out of the park.

I think there a two ways out of this current impasse. 1) forget it and make do with the Astronomik UHC filters I currently have or 2) get the filters from someone who will allow a try before buy basis. 

I am going for the latter and will report on what I find out later down the line.

[Don Pensack]

After your UHC filters, the next filters to get are O-III filters, which are useful on planetary nebulae, Wolf-Rayet excitation nebulae, and supernova remnants.

An H-ß filter has an even narrower bandwidth, making the field quite dark.   It does help make the large faint nebulae like the California Nebula more visible,

but it won't make the horsehead visible in that aperture.

I have held one up to the eye (it was mounted in a small tube to block all peripheral light) which allowed me, at a dark site, to see Barnard's Loop and the Lambda Orionis Complex with the naked eye.

 

So I would advise O-III filters first, then the H-ß filters last.  You have to be completely dark adapted to use them (45-60 minutes outside, away from lights), and use very low powers, like 3-5x/inch of aperture.

One additional comment: your Astronomik UHC filter passes the H-ß line.  If you cannot see an H-ß target in that filter at all, an H-ß filter won't make it visible.

All H-ß targets are visible in the UHC, albeit with a slightly lower contrast.  The H-ß filter helps, but doesn't make visible what was invisible through the UHC.

[bomberbaz]

On 30/01/2022 at 16:43, Don Pensack said:

After your UHC filters, the next filters to get are O-III filters, which are useful on planetary nebulae, Wolf-Rayet excitation nebulae, and supernova remnants.

An H-ß filter has an even narrower bandwidth, making the field quite dark.   It does help make the large faint nebulae like the California Nebula more visible,

but it won't make the horsehead visible in that aperture.

I have held one up to the eye (it was mounted in a small tube to block all peripheral light) which allowed me, at a dark site, to see Barnard's Loop and the Lambda Orionis Complex with the naked eye.

 

So I would advise O-III filters first, then the H-ß filters last.  You have to be completely dark adapted to use them (45-60 minutes outside, away from lights), and use very low powers, like 3-5x/inch of aperture.

One additional comment: your Astronomik UHC filter passes the H-ß line.  If you cannot see an H-ß target in that filter at all, an H-ß filter won't make it visible.

All H-ß targets are visible in the UHC, albeit with a slightly lower contrast.  The H-ß filter helps, but doesn't make visible what was invisible through the UHC.

Good point Don.  Given this, which had crossed my mind but obviously not enough. I think I will simply try again with the UHC filters and leave the HB consideration as just that for the time being, cheers.