ASKAR 151PHQ Remote Observatory Star Spike Issue - Forums

Topic starter

17 days ago

【Help】ASKAR 151PHQ Remote Observatory Star Spike Issue

Equipment: ASKAR 151PHQ + ASI6200MMP + EFW7 Filter Wheel + Antlia 50mm Filters (LRGBPRO + 3nm HSO) + OAGL

⚡ Core Issue:

Narrowband (IC410): HSO channels show no star spikes, while RGB channels display distinct spikes on bright stars, each with different patterns.
Broadband (M45): LRGB channels all show spikes, with intensity in the order L > R > B > G.
Bizarre Phenomenon: The same star in the same channel shows a sudden change in spike shape before and after the meridian flip!

📷 image.png📷 image.png📷 image.png

Troubleshooting Done:
1️⃣ OAG Position: Removed from the optical path, issue persists.
2️⃣ Tube Stress: Opened the roof in advance + adjusted ring tightness, no improvement.
3️⃣ Environmental Factors: Remote observatory temperature variations already considered.

❓ Seeking Advice:

Most likely cause: Filter wheel/filters not perpendicular? Or hidden stress?
Has anyone with similar equipment encountered this issue?
Any recommended quick diagnostic methods?

Detailed images/data available upon request—any guidance is appreciated!

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Tony Gondola

Frequent contributor

17 days ago

I can’t tell a thing from the tiny images posted. Usually when diffraction effects suddenly appear with a refractor it’s because something is in the optical path that was not there before. Has anyone at the remote had a look at the objective to see if there’s something sitting on it that shouldn’t be there?

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TiffsAndAstro

17 days ago

Tony Gondola:
I can’t tell a thing from the tiny images posted. Usually when diffraction effects suddenly appear with a refractor it’s because something is in the optical path that was not there before. Has anyone at the remote had a look at the objective to see if there’s something sitting on it that shouldn’t be there?

A very accurate bird is not impossible

bigCatAstro

Frequent contributor

17 days ago

Could be something as simple as spider web silk in front of the objective. As @Tony Gondola said, can you have someone at the site take a look at the front of the objective and also inspect the rig?

winter summer

Topic starter

16 days ago

This is my first time posting for help. I thought the images I uploaded could be zoomed in for everyone to analyze, so I’m really sorry about that. However, the optical path has been confirmed to be unobstructed, the OAGL has been adjusted to its lowest setting, and technicians have also checked that there should be no foreign objects on the CMOS or filter glass.

M45_SPIKE.jpg

This remote observatory is in a fantastic location. I really don’t want to waste this opportunity. Thank you for any help you can provide.

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jmdl101

16 days ago

I would also double check that the dew shield screw isn't over tightened, those are known to cause pinched optic spikes.

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andrea tasselli

Frequent contributor

16 days ago

Retaining clips in the lenses can do this sort of things, if they aren't careful when placing them or designing the cell. It gets worse in the cold months.