Lines with Lunt 35ha and ASI120MM

alejandrolm

Grettings,

This is Alex, from Barcelona. I have been testing my new equipment (SC8 and ASI120MM). I get some beautiful images of the moon. I had a guiding camera for planetary imaging for a while but now everything is easier. ;)

I have a Lunt35ha, too. When I image the Sun in Ha I get this lines:

Capturing:

Stacked:

Proccessed:

Video:

http://www.youtube.com/watch?v=PdsffNjumDI

Firecapture log:

Scope=Lunt35Ha

Camera=ZWO ASI120MM

Filter=L

Profile=SolHa

Filename=SolHa_050714_Gain=38_Exposure=.6ms_Gamma=98_180527.avi

Date=050714

Start=180527.566

Mid=180542.966

End=180558.367

Duration=30.801s

Date_format=ddMMyy

Time_format=HHmmss

LT=UT+1h

Frames captured=779

File type=AVI

Extended AVI mode=false

Compressed AVI=false

Binning=no

ROI=1280x960

FPS (avg.)=25

Shutter=0.592ms

Gain=38

USBTraffic=80

AutoExposure=off

Brightness=0

Gamma=98 (off)

Histogramm(min)=113

Histogramm(max)=153

Histogramm=60%

Noise(avg.deviation)=18.20

Limit=none

Sensor temperature=47,8 ∞C / 118,1 ∞F

Unfocused image:

I have been playing with settings and I get the same results. However, if I adjust exposure to get the prominences, the lines disappear:

As I said, no problems in the moon or planets. I get this lines even changing USB wire, rotating the star diagonal or camera, changing between ASI120mm and Nexi5, using Sharcap, Firecapture, iCap... The problem is the telescope, I guess.

Some help here? Thanks in advanced.

Alex

riklaunim

Micron CMOS sensors are known to give Newton rings in narrowband solar telescopes. The only way to deal with them is by using flats or a camera with a different, non Micron sensor.

Sensor given Newton rings do not change intensity when the camera gets tilted. Rings caused by given camera orientation can be removed by playing with the camera tilt/orientation in the telescope focuser.

Sam@ZWO

great images

you can have a look at here:

http://www.schursastrophotography.com/solar/Articles/solararticle5.html

skywatcher

hello,

i also have so the ASI 120mm and lunt 35

to remove the newton ring, the best way for me is with IRIS :

http://zwoug.org/viewtopic.php?f=21&t=1608

to remove the very small lines, an offset can be used

I also noticed when checking the gamma box, and setting the value to 50%, it improves things

I had a flat with very classic stretch film for Food Packaging placed before the lunt, and it works !

but i don t touch the focus with this method !