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Baader Ha 7nm verses 3.5nm


Sp@ce_d

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Just trying out one of the new Baader Enforced 3.5nm Ha filters, while testing the new setup (EQ8, another Esprit & some bits).

Thought I'd post a couple of comparison subs. Both subs of 900s, with a pair of Esprit 80's, Atik 314L+'s.

Unfortunately I couldn't frame them exactly as the ADM Max guidescope saddle is at maximum azmith adjustment so I'll need to have a look at that, maybe turn it around.

Just a quick STF stretch in PI.  I probably need to try a few more targets for comparison before I judge whether to go down the Astrodon route.. as I think I was expecting to notice a bit more difference from my 7nm. Anyway your thoughts..

Baader Ha 7nm

post-11176-0-75491700-1413936110_thumb.p

Baader Enforced 3.5nm

post-11176-0-80246800-1413936113_thumb.p

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The scopes seem vastly different. Is one pinched? We really need to see them on the same scope and camera for a real comparison ;)

/per

Well, both scopes are Esprit 80's. Both scopes have the SW flattener attached. Both cameras are Atik 314L+'s. Mounted side by side on (yes I finally took the plunge) an EQ8 also getting its "first light".

The 3.5nm is actually first light for the Esprit 80 I got to replace the GT81 I had issues with bad diffraction & the star shapes. I was "assuming" the stars would have been smaller with the 3.5nm filter too.

Difference in focussing. My original Esprit 80 was focussed using focusmax. As I haven't fitted a motor to the new one yet I used a Bahtinov for the 3.5nm.

The 3.5nm is a 2" filter screwed into the flattener. Spacing to CCD made up using new tubes. Not the ones used on the GT81. However, thinking about it I reckon this is the same CCD (Ihave 3)

The 7nm is in a filter wheel. I also have a Hutec LPS P2 2" screwed into the Flattener on this one.

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I agree with Per.

The star shapes on the scope with the 3.5nm filter fitted are pretty terrible.  I'd definitely try swapping the filters over and seeing if the bad star shapes are still there or move scopes with the filter change.   It could well be the filter causing the effect but you need to rule out the possibility that you have a duff scope.

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I agree with Per.

The star shapes on the scope with the 3.5nm filter fitted are pretty terrible.  I'd definitely try swapping the filters over and seeing if the bad star shapes are still there or move scopes with the filter change.   It could well be the filter causing the effect but you need to rule out the possibility that you have a duff scope.

Yes, I intend to swap them around to test & see. Once this cloud heads away :sad:

Will be a bit annoying if it is the scope after the return of the GT81 for similar issue, but then also annoying if its the filter :huh:

Anyway, more tests needed before jumping to conclusions.

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Some clearish sky at last tonight, although seeing is naff. As I only have one 3.5nm Ha I'm running the 2 Esprits with a selection of like for like filters at same time for comparison.

Meanwhile, I've run the 3.5nm on the ZS71 to prove/disprove any issue with the filter. Still tweaking PA/balance & guiding on the EQ8 but aside from slight eggs the stars look ok. Which points to the scope :(

ZS71 Baader 3.5nm HA

post-11176-0-91212100-1414540748_thumb.p

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Yup.. filters fine.. scopes suspect.

I swapped the whole imaging train over inc. flattener. Stars still look like a 50 pence piece. :cry:

Both subs taken at same time..

The new Esprit with whole imaging train swapped over from my original setup.

post-11176-0-41506000-1414544139_thumb.p

My original Esprit with swapped CCD & flattener (+added FW & Filterset)

post-11176-0-20982000-1414544143_thumb.p

Crop

post-11176-0-23146000-1414544794.png   post-11176-0-17652200-1414544795.png

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Id be interested to se a Sadr region comparision, and see how he filter deals with a bright star in the field. thats the money shot for filters imo

Funny you should say that, I tried pointing the rigg in that direction last night but clouds beat me to it. Forecast isn't too good for a bit either. The dodgy Esprit is going to be replaced, so I may well have it setup by the time it clears.. ready for the full Moon ;)

Otherwise I'll grab one with the ZS71 in the meantime

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Here we go, a quick Sadr. 3.5nm on the ZS71 and 7nm on my original Esprit. I've got a 2" 7nm I'm going to swap out for the 3.5nm on the ZS71 for equal comparison with if I get a chance in the week.

I'm not sure what to make of this to be honest. I was expecting tighter star control with the 3.5nm. There's definitely a problem with the star shape on the newer Esprit in the thread earlier, as it persists on the other filters & imaging train that works fine on my original Esprit. However, I think the 3.5nm filter exasperated it the most.

Now looking at this region with the 3.5 nm filter on the ZS71 it doesn't look as I was expecting either. So the question is why does Sadr look more like a globular through this filter? Is it just the way I've done an auto STF stretch in PI to show them with equal stretch here?

Both a bit noisy.. I forgot to switch on the coolers in my haste for the gap in clouds..

ZS51 with Baader 3.5nm Ha - 900s

post-11176-0-59156100-1414970107_thumb.p

Esprit 80 with Baader 7nm Ha - 900s

post-11176-0-22316700-1414970111_thumb.p

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The test needs to be with the same optics or we cannot say anything. I do not think the star-bloating in the 3.5nm image comes from the filter. Do you?

All the best,

Per

Well, I'm going to put a 7nm on the ZS71 & compare that next as I'm already halfway down that route now.

Do you think the bloating on Ha is because its a doublet then? or because its not a Tak :grin:

Also then.. would I be seeing similar stars with an Astrodon 3nm?

I'll also try the 3.5 on my "good" Esprit.

I agree with Earl at this point.. I prefer the 7nm.

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  • 1 year later...

The difference is far less than I see between my Astrodon 3 and my Baader 7. It is indeed target dependent but the star sizes in the Astrodon 3 are a fraction of those from the Baader 7. Contrast may be far higher or not that different, depending on the strength of the NII line I suppose.

Most of the time the Astrodon 3nm is way, way better than the Baader 7 and is not, contrary to what you might expect, slower. Here I see no big deal of a difference but the scope and focus may well be distorting the result. The Baader is a dog to focus, though. Frequently I find no suitable star in an image and have to slew away.

Olly

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6 hours ago, ollypenrice said:

The difference is far less than I see between my Astrodon 3 and my Baader 7. It is indeed target dependent but the star sizes in the Astrodon 3 are a fraction of those from the Baader 7. Contrast may be far higher or not that different, depending on the strength of the NII line I suppose.

Most of the time the Astrodon 3nm is way, way better than the Baader 7 and is not, contrary to what you might expect, slower. Here I see no big deal of a difference but the scope and focus may well be distorting the result. The Baader is a dog to focus, though. Frequently I find no suitable star in an image and have to slew away.

Olly

mmm I think my FSQ106 and focus are fine! 

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5 hours ago, astrodude said:

mmm I think my FSQ106 and focus are fine! 

In which case there is less difference between your tested filters than between the Astrodon 3 and the Baader 7. I'll try to put a comparison from my own results up when I get a sec.

Olly

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OK, see what you think here. In a recent project on a Jellyfish region mosaic I used our twin Tak 106 rig (3.5 arcsecs per pixel) and our TEC 140 (1.8 arcsecs per pixel) to gather the data. Naturally I used the TEC to enhance the most interesting parts like the Jellyfish, M35 and the Monkey Head. The TEC, not surprisingly, out resolves the Takahashis quite convincingly. Even when resized downwards to match the Tak data the TEC clearly shows better resolution in this RGB only section, quickly processed with no fancy tricks and no sharpening.

Takahashi FSQ 106:

M35%20Tak%20106.jpg

 

TEC 140:

M35%20TEC%20140.jpg

But now look what happened when we shot the Jellyfish using the Astrodon 3nm in the Taks and the 7 nm in the TEC. The stars are actually smaller in the Tak image this time and, in my view, there is little to choose between the nebulae, though I think the Tak data is better.

TEC 140 7 nm Ha:

Ha%20TEC%207nm.jpg

Takahashi FSQ106 3nm Ha:

Ha%20TAK%203NM.jpg

Using the same filters the TEC usually out resolves the Taks by quite a margin. Put a 3nm Astrodon in the Tak and a 7nm Baader in the TEC and that margin all but disappears.

Well, so it seems to me, but agreement isn't compulsory!

:Dlly

 

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Interesting images. To be scientifically sound though, if you are comparing two filters they need to be placed on the same optical train, using the same sensor, focussed by the same method and any images taken under the exact same conditions including atmospheric seeing and altitude of target. Then they need to be processed using identical parameters. Plus when converting to online posting format they need to be converted in the same way. It would be interesting to compare several Ha filters from a variety of manufacturers under such conditions. Alas though my pockets are not deep enough and clear skies too valuable to spend much time on such issues. My imagers were posted purely so anyone curious/interested about the Baader Ha filters and their difference in bandwidth could directly compare them.  Regards.

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  • 2 years later...

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