Filters for visual observing

[DRT]

I have been looking into buying an H-beta filter to have a go at the Horsehead nebula and have a question about quality that I hope will elicit answers more helpful than "just buy the most expensive one"

H-beta filters seem to range in price from the Skywatcher 1.25" at around £28 to the Astranomik at £73 and the Baader at £89 and presumably upwards from there.

For imaging I can definitely understand why going for very high quality filters would improve your chances of bringing out the best from your telescope, camera and processing abilities - but my question is, how much difference would I see with my eye between the relatively inexpensive SW filter and the more expensive alternatives?

 

[scarp15]

Hi Derek, I have a 2" Lumicon H-beta filter. The reasons I have this are that my primary interest is to venture out as often as possible (never enough of course) to go observing at dark sky locations and I have developed a particular appetite for nebula hunting, in pursuit of the fairly straight forward to the quite challenging. My other reason for the Lumicon is  because I now have the set that includes 2" O-III and UHC. The H-beta filter probably enables much larger exit pupils to be used and so far the most interesting object I have glimpsed is the California. Whist this filter is integral, it does not, nor do I expect it to, provide a sensational image such as selective objects that the OIII in particular is capable of revealing. It is therefore a discerning tool, though if you do consider B33 as a contender (and there are many others besides), then it would be beneficial, if you are up for a challenge and can go to dark sky locations. I cannot comment on other brands, the Lumicon filters continue to provide very rewarding encounters.

[DRT]

Thanks, Iain. I think (and I am making a bold and brave statement here) that I have read enough to understand why the various types of filters allow us to see various objects and as H-beta is something that I do not currently have in my armoury I have decided to buy one.

I already own a small mountain of filters, all but one of which are Baaders. The other is the TV Planetary filter, which was even more Astranomik(al) than an Astranomik

The question at hand is: will I see a benefit in spending three times more on a Baader H-beta filter rather than plumping for the £28 job from Skywatcher? I am really hoping that someone who has looked through both will chime in

 

 

[jetstream]

I have 2 Hb's, an Astronomik and a Lumicon, so far the Astronomik wins. I also have owned an Orion Ultrablock- Orion has been affiliated with SW, at least in the past- and its performance was poor. Presumably we pay more for consistent filter specs, but from my limited experience Astronomik gives very good performance at a bit wider bandwidth.

The "luck of the draw" seems to be a factor with many filter brands.

The difference between my Ultrablock and Lumicon UHC is dramatic.

[DRT]

Thanks, Gerry, that's the kind of experience I was hoping to benefit from.

Does anyone have a view on Baader v Astronomik? My preference is to buy a 2" as I could fit it to a diagonal or 1.25" to 2" adapter and swap eyepieces without touching it. Baader doesn't give me that option as far as I can see so it might be the Astronomik by default

 

[Stu]

My only experience in terms of comparisons is a skywatcher OIII vs Lumicon OIII. No comparison, the Lumicon is way better, significantly better contrast due to its narrower band pass.

If it helps, I have a Lumicon H beta 1.25" which I bought used and have never had the chance to use. You are welcome to use it at SGL12 (is it 12, can't remember!) if you like.

[Paul73]

Interesting thread. 

I've got John's old Lumicon 1 1/4" Hb. The only reason that I went for that is because I was so impressed with their O111 (have got the 1 1/4" and 2" formats).

Obviously. Buying new is out of the question unless some one still has a bit of old stock kicking around. So I would buy now whilst they are fairly plentiful on the second hand market.

Paul

[John]

I'd go for the best quality filter I could get. H-Beta targets are often right at the edge of the performance envelope of scope / conditions / observer so I figure that you want to tilt everything you can in your favour.

That said I've used 2 excellent H-Beta filters (1000 Oaks and Lumicon) and am embarrassed to admit that I saw nothing much through them (of the Horsehead or other H-Beta suitable targets) with my 12" dob even under the best conditions I get here at home

Thats probably a comment on my viewing conditions here more than filter ability though

I've sold my Lumicon H-Beta now (to Paul) and stick now with my DGM NBP and Lumicon O-III for deep sky viewing. If I go to a really dark site again with the 12" I may try a H-Beta filter again I guess.

[DRT]

Thanks, guys. All very helpful replies.

I take it from @Paul73's reply that Lumicon are no more? I didn't know that, but it explains why I found nothing when searching to get a retail price for one

@Stu - generous to a fault as usual - thank you, I will certainly take you up on that offer, although I think the only thing we are likely to see through it at Lucksall in October is the nebula emanating from the kitchen when they cook @tich's supernova breakfast

@John - "I'd go for the best quality filter I could get" is where I suspected this would end up - I was just living in hope that someone would tell me that the £28 SW H-b would be fine

Hi-ho, hi-o, it's of to Astonomik(al) we go...

 

 

 

 

[John]

I believe Moonshane tried a Skywatcher H-B filter for a while. I don't recall that he reported miraculous results from it but I might have missed the reports

It's important to think about the exit pupil with filters and perhaps with the H-Beta even more than the UHC and O-III types. From field reports I've read getting the right exit pupil can make all the difference between perceiving a faint object and not.

 

 

[Piero]

Hi Derek, 

I have both the Astronomik UHC and OIII in 1.25" format. Never tried (and possibly never will! LOL!) the H-beta simply because the list of targets is quite restricted and quite demanding in terms of sky darkness.

The Astronomik filters are very good and also very solid in my opinion. They complement each other I would say so it is always hard to give advice if only one filter is going to be purchased. Possibly under moderately light polluted skies I would opt for a OIII filter, as this can be a nice weapon on planetary nebulae. On the other hand sweeping the Milky Way under dark skies with an UHC filter on can be a nice experience. 

Two things I want to say though. 1) I would definitely get a 2" filter. It is far more flexible and all these filters work well at low power too. With your collection of Ethoi, I dare to say that you will be very sad not to use an OIII filter with your Ethos 21 and your big dob! The only reason why I bought the 1.25" size is because my TV60 only accepts 1.25" diagonals. 2) I would buy a high quality one. They are expensive, but it is not something you are going to change. They are also very robust nowadays. Lumicon OIII seems a winner. I believe it can show slightly better contrast than the Astronomik OIII because its passing band is shorter. Also, the left and right lines are steeper which might also cause (although this is an hypothesis) an increase in contrast to me. You won't go wrong with the Astronomik OIII anyway. It's a great filter. If you intend to use these filters with small telescopes, I can tell you that the Astronomik filters work well with my 60mm, so every larger telescope will work just fine.

This is worth reading to me: http://www.cloudynights.com/topic/527199-spectroscopic-analysis-comparison-of-nebula-filters/

Cheers, 

Piero

[Scooot]

25 minutes ago, DRT said:

Thanks, guys. All very helpful replies.

I take it from @Paul73's reply that Lumicon are no more? I didn't know that, but it explains why I found nothing when searching to get a retail price for one

@Stu - generous to a fault as usual - thank you, I will certainly take you up on that offer, although I think the only thing we are likely to see through it at Lucksall in October is the nebula emanating from the kitchen when they cook @tich's supernova breakfast

@John - "I'd go for the best quality filter I could get" is where I suspected this would end up - I was just living in hope that someone would tell me that the £28 SW H-b would be fine

Hi-ho, hi-o, it's of to Astonomik(al) we go...

 

 

 

 

Here Derek, quite pricey at current exchange rates.

https://www.lumicon.com/store/p/81-2-H-beta-Hydrogen-Beta-Filter.aspx

[Stu]

Without wishing to be accused of getting too theoretical, which has happened a couple of times recently, here are some potentially useful links. The first one covers a lot of ground but is, I think very useful for understanding all this stuff. The second is an oft quoted piece from Barbara Wilson about the correct eyepiece to try to see the Horsey with.

http://www.rocketmime.com/astronomy/Telescope/SurfaceBrightness.html

http://home.ix.netcom.com/~bwilson2/barbarasweb/MEyepiece.htm

[Mark at Beaufort]

Derek I have viewed the Horsehead only once and that was at Lucksall Star Party using an Astronomik H.Beta on a 16" Dob. I have a 1000 Oaks H.Beta (this is one John tried) and have failed to see the HH at home with my 10" and now 12" scope. I have read that you can use a UHC to view the HH but an O-III is to be avoided. Also, the magic bullet eyepiece can be a 25mm Plossl.

With regard to price and quality I have a Skywatcher UHC, Lumicon UHC and Baader UHC and the Lumicon is so much better. I have tried several O-III filters and I rate the Astronomik my favourite.

 

[Stu]

20 minutes ago, Mark at Beaufort said:

Derek I have viewed the Horsehead only once and that was at Lucksall Star Party using an Astronomik H.Beta on a 16" Dob. I have a 1000 Oaks H.Beta (this is one John tried) and have failed to see the HH at home with my 10" and now 12" scope. I have read that you can use a UHC to view the HH but an O-III is to be avoided. Also, the magic bullet eyepiece can be a 25mm Plossl.

With regard to price and quality I have a Skywatcher UHC, Lumicon UHC and Baader UHC and the Lumicon is so much better. I have tried several O-III filters and I rate the Astronomik my favourite.

 

Mark is correct about the UHC being ok for the Horsehead. The UHC band pass includes the H Beta line (along with the two OIII lines), whereas the OIII cuts H Beta out.

[nicoscy]

Just to put down a "list" of things to consider when attempting the HH for the first time. You need the following:

• A Hb filter ideally (although it can be seen with a UHC, but contrast is markedly reduced and for first attempts, best to stick with Hb - borrow one to try if necessary)
• A large exit pupil (typically 5mm +)
• FULL dark adaptation (not only your typical 30 or so minutes, but also the last few minutes before attempting it should be spent with any red lights off)
• A blanket / hoodie to shield your eyes from any ambient light (makes an unbelievable difference) and do stay under the blanket for a couple of minutes prior to attempting the HH)
• Dark skies (preferably SQM reeadings in excess of 20). No dark skies, no horsehead - as simple as that
• A decent chart with correct orientation of the object and an idea of its size (it is larger that the observer tends to think)

I have so far detected the HH with 18", 16", 12", 6", 5", 4" and this winter I shall attempt 90mm, 76mm and 70mm. While I am confident I will manage the 90, the 76 and 70 will probably prove impossible, but still...

EDIT: Opinions are divided if Alnitak should be in the FOV or not. I find that it helps me if it is in the FOV, others find the glare distracting...

[nicoscy]

Also, for a list of items that can be seen with a Hb, I attach a list in EXCEL. Have fun!

Filters list of objects.xlsx

[Paul73]

Blimey Nicos! you must get to some properly dark sites.

This one is on my "OK to obsess about" list for this winter.

Thanks for the succinct Horsey hunting checklist.

My starting kit is 16" Dob, 18mm BCO @5mm exit pupil (I tend to do better with no bright stars for "first sights"), Lumicon Hb filter.

Paul

[nicoscy]

Paul, 

I have 3 dark sites within 50 minutes from home with SQM readings of 21.2 - 21.3 and a dark site with SQM readings or 21.7 but that one is 3 hours away - too long a drive!

So, skies are pretty good where I am at. I was just stating that SQM 20 + is a bare minimum to try the horsehead 

Best of luck this winter. On January 2014 when I got my 12" OO VX12 f4, first light was the horsehead and it sure was pretty 

Your 16" should provide a blindingly obvious image of the Horsehead. As a treat, I attach an image of the exact orientation and how it will look with the FOV of your eyepiece and telescope combo.

As you can see, the damned thing is huge!

[nicoscy]

Alnitak is at the left and slightly below of the HH BTW.

[nicoscy]

And here is another one with a larger FOV.

[Paul73]

Cracking first light!!!

I believe that Derek will be using the same scope. Unless he has been shopping ........

Paul

[John]

5 hours ago, nicoscy said:

Just to put down a "list" of things to consider when attempting the HH for the first time. You need the following:

• A Hb filter ideally (although it can be seen with a UHC, but contrast is markedly reduced and for first attempts, best to stick with Hb - borrow one to try if necessary)
• A large exit pupil (typically 5mm +)
• FULL dark adaptation (not only your typical 30 or so minutes, but also the last few minutes before attempting it should be spent with any red lights off)
• A blanket / hoodie to shield your eyes from any ambient light (makes an unbelievable difference) and do stay under the blanket for a couple of minutes prior to attempting the HH)
• Dark skies (preferably SQM reeadings in excess of 20). No dark skies, no horsehead - as simple as that
• A decent chart with correct orientation of the object and an idea of its size (it is larger that the observer tends to think)

I have so far detected the HH with 18", 16", 12", 6", 5", 4" and this winter I shall attempt 90mm, 76mm and 70mm. While I am confident I will manage the 90, the 76 and 70 will probably prove impossible, but still...

EDIT: Opinions are divided if Alnitak should be in the FOV or not. I find that it helps me if it is in the FOV, others find the glare distracting...

Some great practical advice Nicos with positive results too !

 

[alan potts]

Hi Derek,

I have the Astonomik's H beta only because I couldn't get the Lumicon who I later found have stop trading. From what I gather there really is little between these two, both being very high quality. I had a good few trys at the HH and was not able to see it from here with the 18 inch. I really wish I had bought the 2 inch which I didn't (cheapskate), this was because i thought a 4mm Exit would give me the best chance, this I can get with the 24mm Panoptic and a 1.25 filter. The 2 inch is very expensive, I was quoted close to 200 pounds and lets face it that's, or was, a De-lite eyepiece.  

[Mark at Beaufort]

This thread goes back to a question that is often asked. How much should I spend to get a good result on objects like 'The Veil', M27, M42, M8, M17 etc etc.

The purest will state you must buy a Lumicon or Astronomik whether its an O-III or UHC or maybe an Omega/DGM NPB - but are you willing to spend £130/£150 plus on a 2" Filter to get these results.

So the question really is how good is a Castell, TS or Explore Scientific UHC, O-III or H.Beta? Is it worth spending £70 on one of these 2" Filters to get an improvement that will satisfy you.

I have used a Skywatcher and Baader UHC which were not bad. I had a TS O-III which was pretty good and not a lot different to an Astronomik O-III.

I know some will say that the bandwidth of the ES and Castell is too wide but if it get a result is that a problem?

So to get to Derek's original question - is it worth spending a lot more simply to get a 'named' filter or should the money be better spent on a better eyepiece?

PS - I should state that I currently use a Lumicon UHC, Astronomik O-III and a 1000 Oaks H.Beta but also have a Skywatcher UHC and a Baader UHC-S