15 replies to this topic

[GeezerGazer]

I had been thinking about buying a 2" Chroma 8nm H-a filter to replace both my 12nm and 7nm H-a filters.  I last checked on the price at the beginning of December, when it was $475... which was within the realm of possibility for me.  Now ready to pull the trigger, I am met with a MUCH higher cost.  

 

Chroma filters have taken a major hike in pricing!   2" H-a filters are now: 

  8nm     $830  (57% price increase)

  5nm     $975

  3nm     $1300

 

From my perspective, these fine US made filters are now priced beyond my means, and no amount of justification will permit me to make such an expenditure.  Most unfortunate timing for the price hike, especially as excellent filters are being offered from China at ~30% of Chroma's pricing for similar pass bands. I expect to see a similar increase in Astrodon filters (FarPoint), which may be manufactured by Chroma.  

Edited by GeezerGazer, 02 January 2021 - 05:15 PM.

[Jeff Morgan]

Before Christmas I placed an order for a Chroma 3nm from Woodland hills - had a gift coupon to burn there. Filled the order out as a purchase order and they said they would call me back to complete the order.

 

They never called. Must not have been able to fulfill at the old price.

[PEterW]

There is a note in the vendor thread where they apologise for not warning resellers and that they should have slowly increased the price, rather than just a big step. It is unfortunate given the nebula results people report with them.

PEter

[RedzoneMN]

What are the options for 3 nm filters that are reasonably priced?

 

It seems that Antlia is coming out with 3 nm but the wait may be long. Any other contenders that are worthwhile?

[jay.i]

What are the options for 3 nm filters that are reasonably priced?

 

It seems that Antlia is coming out with 3 nm but the wait may be long. Any other contenders that are worthwhile?

The Antlia 3.5nm Ha and 3nm Ha PRO filters are both on the market. The 3.5nm seems to be out of stock everywhere in 2", but Agena has the 3nm Ha PRO filter in 2" for $430.

 

https://agenaastro.c...-2-mounted.html

 

I ended up getting the 3nm instead of the 3.5nm as a mistake and ended up keeping it for a discounted upcharge, and I was impressed with what I saw, given enough light. The Horse Head was pretty impressive from my Bortle 7 skies + Borg 90FL (f/5.6) afocal with TV67 and 0.75x reducer (~5.6x, f/1.6). Even without the reducer (~7.5x, f/2.2) it looked great, plenty of extension, still plain to see, with the Flame looking quite detailed.

 

Note that this photo was NOT taken with the 3nm as I remembered; there are far too many stars. This is either my 7nm Astronomik or, maybe even my 642nm Astronomik. Not sure. But the visual image of the Horse Head and Flame nebulae was equally impressive, visually, with the 3nm. 

Attached Thumbnails

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Edited by jay.i, 03 January 2021 - 01:40 PM.

[RedzoneMN]

The Antlia 3.5nm Ha and 3nm Ha PRO filters are both on the market. The 3.5nm seems to be out of stock everywhere in 2", but Agena has the 3nm Ha PRO filter in 2" for $430.

 

https://agenaastro.c...-2-mounted.html

 

 

Thank you. Just snagged one. 

[gatorengineer]

Problem for some with the Antilias is that they are not front threaded.....

 

The Astro Market for Chroma must be just too much of a niche...... and hence they want out of it.  A shame, now we will have to import our filters like almost every other piece of astro gear.... Not sure I can think of anything American Made other than Mike Lockwood Mirrors, and a few US plywood shops.  

[Jeff Morgan]

ScopeStuff sells empty filter rings in 1.25" and 2" format. Threads on both sides.

 

http://www.scopestuff.com/ss_tifr.htm

[RedzoneMN]

ScopeStuff sells empty filter rings in 1.25" and 2" format. Threads on both sides.

 

http://www.scopestuff.com/ss_tifr.htm

Jeff, can they be used with the Antlia 3 nm mounted rings or are they only for unmounted glass?

 

Thank you 

Red

[Jeff Morgan]

Jeff, can they be used with the Antlia 3 nm mounted rings or are they only for unmounted glass?

 

Thank you 

Red

I believe you would need to unthread the Antlia filter retaining ring and remove the glass.

 

Note also that the ScopeStuff ring is relatively thick. Probably a no-go if you are using a filter slide or wheel.

[jay.i]

Why does a filter need to be front threaded if you're not stacking filters? It should always be as close to the light source as possible (e.g. in front of the diagonal/reducer/eyepiece). As long as the diagonal and/or reducer is front threaded (depending on your configuration) I see no reason why the filters need to be.

[gatorengineer]

For me with the ASA stack, I need to put the filter after the ASA and before the Eyepiece, and thread it both sides.

[jay.i]

For me with the ASA stack, I need to put the filter after the ASA and before the Eyepiece, and thread it both sides.

So you're directly threading the eyepiece to the reducer, with the filter sandwiched in the middle? Is there any reason you can't put the filter in front of the reducer (away from the eyepiece)?

[gatorengineer]

The reducer I am using has a very aggressive convex lens and is not front threaded.  hence I cant mount it in the usual location as I would with a paracorr.

[jay.i]

The reducer I am using has a very aggressive convex lens and is not front threaded.  hence I cant mount it in the usual location as I would with a paracorr.

Gotcha, the convex lens would do it! Bummer that it limits your filter use though.

[GeezerGazer]

Jeff, can they be used with the Antlia 3 nm mounted rings or are they only for unmounted glass?

 

Thank you 

Red

Red, 

As Jeff explained, the Antlia filter must be disassembled by removing the lock ring. 

The 2" ScopeStuff filter cell appears to be the same as the Blue Fireball filter cell sold by Agena, found here:  https://agenaastro.c...-cell-s-2f.html

And it can be used with the Antlia 2" 3.5nm filter... with the following adjustments.

 

The Antlia filter does fit nicely in this cell.  But I had to find a different lock ring for the cell, because the stock lock ring is very thick.  By the time a 2mm thick filter is installed and the Blue Fireball lock ring is added, there are no front filter threads left to use.  So I used a thinner lock ring from a Neewer filter which worked perfectly and left about 2.5mm of front threads.

 

The Antlia filter glass does fit the Blue Fireball cell nicely.  However, It did not fit a Neewer cell that I tried first.  Conversely, a 2" Optolong filter fit the Neewer filter cell but not the Blue Fireball.  There is a few millimeters difference between the diameters of these two glass filters.

 

jay.i, in answer to your question about why front threads might be needed, I use 2" filters as part of my Nikon camera lens adapter, seen in the photos below.  The Blue Fireball cell is very stout for a strong connection, but it is thick with a light path of about 7mm.  You can see it in the photos with the smooth silver line on the rim.  This adapter system uses a RAF C-mount to M48 adapter, the filter cell, an M48 to M42 adapter and the M42 to Nikon adapter.  I use it with each of my four prime lenses, including an f:2.8 300mm, with excellent results. 

 

2" Antlia 3.5nm filter in a Blue Fireball filter cell

 

Filter cell installed between C-mount NVD and Nikon adapter

 

With 50mm camera lens attached

Edited by GeezerGazer, 06 January 2021 - 11:12 PM.