2 replies to this topic

[lpalbou]

Hi everyone,

 

While both my quarks get repaired (..), I decided to buy a Lunt 40 as I also want to try a rear-mounted MOD and double stacking it with a quark when I get them back.

 

I must say the real-time tuning of the Lunt is so nice compared to Quark.. Don't get me wrong, I still love my quarks and that's why they are in repair; but I will continue to investigate more and more the pros of Lunt & Quark in the future, my hope going toward the double stack MOD Lunt/Quark to have nice and clean limb.

 

Normal Contrast BW

 

Normal Contrast Color

 

Inverted Contrast BW

 

Inverted Contrast Color

 

 

Overall, I am quite impressed by the Lunt 40, both in terms of optics, etalon and convenience. The only drawbacks I see:

1) provided you have a good quark, they can actually better filter the limb to avoid the large double limb seen here

2) it is only my second test with the Lunt 40 but it seems the etalons doesn't have the same band left to right (e.g. see the additional white plage on the right, compared to my BW image in normal contrast) :

 

 

It is posssible that by tuning more the Lunt, it would get a better Ha filtering but at the same time, I can see it changes the overall illumination with one side of the sun being much darker. If you have tips, I am all ear as I am still discovering this Lunt 40

Edited by lpalbou, 17 July 2024 - 06:58 AM.

[gstrumol]

If you compare your first image with the GONG image you'll see that pretty much the right side is off-band. This may be the result of improper tuning and/or placing the disk outside of the 'sweet spot'. This results in missing the filaments and plages in those regions. It also contributes to the variable illumination across the disk.

[lpalbou]

I agree and that’s also my conclusion when i consulted the gong image and why i made this post. However this was the tuning with the best homogeneous illumination : eg i didn’t use any flat here and one can see the field of illumination is pretty nice and centered.

This would suggest the best on band tuning is not necessarily the best homogeneous illumination. I would like to confirm that that statement with other Lunt owners ?

 

PS : as far as placing the disk outside the sweet spot, i am using a 290M with a fairly small fov so the sun is anyhow taking >70% of the screen. Not much to optimize here with that sensor and with a BF600, fairly small. 

Edited by lpalbou, 17 July 2024 - 11:23 AM.