Tools & Wizards About Us
xrtpub.harvard.edu screenshot

Report Summary

  • 19

    Performance

    Renders faster than
    36% of other websites

  • 92

    Accessibility

    Visual factors better than
    that of 78% of websites

  • 50

    Best Practices

    More advanced features
    available than in
    19% of websites

  • 78

    SEO

    Google-friendlier than
    39% of websites

xrtpub.harvard.edu

Chandra X-ray Observatory - NASA's flagship X-ray telescope

Page Load Speed

5.1 sec in total

First Response

1.7 sec

Resources Loaded

3.2 sec

Page Rendered

220 ms

xrtpub.harvard.edu screenshot

About Website

Visit xrtpub.harvard.edu now to see the best up-to-date Xrtpub Harvard content for United States and also check out these interesting facts you probably never knew about xrtpub.harvard.edu

NASA's sophisticated telescope is specially designed to detect X-ray emission from very hot regions of the Universe.

Visit xrtpub.harvard.edu

Key Findings

We analyzed Xrtpub.harvard.edu page load time and found that the first response time was 1.7 sec and then it took 3.4 sec to load all DOM resources and completely render a web page. This is a poor result, as 60% of websites can load faster.

Performance Metrics

xrtpub.harvard.edu performance score

19

Measured Metrics

name

value

score

weighting

FCP (First Contentful Paint)

Value3.9 s

25/100

10%

LCP (Largest Contentful Paint)

Value13.8 s

0/100

25%

SI (Speed Index)

Value29.7 s

0/100

10%

TBT (Total Blocking Time)

Value2,650 ms

4/100

30%

CLS (Cumulative Layout Shift)

Value0

100/100

15%

TTI (Time to Interactive)

Value41.8 s

0/100

10%

Network Requests Diagram

xrtpub.harvard.edu

1720 ms

cxcpub_topmenu.css

39 ms

cxcpub_slider.css

41 ms

cxcpub_wsn.css

64 ms

cxcpub_topnav_home.css

41 ms

Our browser made a total of 214 requests to load all elements on the main page. We found that 57% of them (121 requests) were addressed to the original Xrtpub.harvard.edu, 9% (20 requests) were made to Platform.twitter.com and 9% (19 requests) were made to Live.staticflickr.com. The less responsive or slowest element that took the longest time to load (1.7 sec) belongs to the original domain Xrtpub.harvard.edu.

Page Optimization Overview & Recommendations

Page size can be reduced by 918.6 kB (22%)

Content Size

4.2 MB

After Optimization

3.3 MB

  • HTML
  • Images
  • JavaScript
  • CSS

In fact, the total size of Xrtpub.harvard.edu main page is 4.2 MB. This result falls beyond the top 1M of websites and identifies a large and not optimized web page that may take ages to load. Only a small number of websites need less resources to load. Images take 3.3 MB which makes up the majority of the site volume.

HTML Optimization

-83%

Potential reduce by 116.4 kB

  • Original 140.6 kB
  • After minification 133.7 kB
  • After compression 24.2 kB

HTML content can be minified and compressed by a website’s server. The most efficient way is to compress content using GZIP which reduces data amount travelling through the network between server and browser. HTML code on this page is well minified. It is highly recommended that content of this web page should be compressed using GZIP, as it can save up to 116.4 kB or 83% of the original size.

Image Optimization

-14%

Potential reduce by 472.7 kB

  • Original 3.3 MB
  • After minification 2.9 MB

Image size optimization can help to speed up a website loading time. The chart above shows the difference between the size before and after optimization. Obviously, Xrtpub Harvard needs image optimization as it can save up to 472.7 kB or 14% of the original volume. The most popular and efficient tools for JPEG and PNG image optimization are Jpegoptim and PNG Crush.

JavaScript Optimization

-46%

Potential reduce by 276.1 kB

  • Original 598.3 kB
  • After minification 579.3 kB
  • After compression 322.3 kB

It’s better to minify JavaScript in order to improve website performance. The diagram shows the current total size of all JavaScript files against the prospective JavaScript size after its minification and compression. It is highly recommended that all JavaScript files should be compressed and minified as it can save up to 276.1 kB or 46% of the original size.

CSS Optimization

-44%

Potential reduce by 53.4 kB

  • Original 120.3 kB
  • After minification 104.2 kB
  • After compression 66.9 kB

CSS files minification is very important to reduce a web page rendering time. The faster CSS files can load, the earlier a page can be rendered. Xrtpub.harvard.edu needs all CSS files to be minified and compressed as it can save up to 53.4 kB or 44% of the original size.

Requests Breakdown

Number of requests can be reduced by 67 (33%)

Requests Now

205

After Optimization

138

  • AJAX
  • Images
  • JavaScript
  • CSS

The browser has sent 205 CSS, Javascripts, AJAX and image requests in order to completely render the main page of Xrtpub Harvard. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 55 to 1 for JavaScripts and from 8 to 1 for CSS and as a result speed up the page load time.

Network Requests Diagram

xrtpub.harvard.edu

xrtpub.harvard.edu

1720 ms

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39 ms

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make.png

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calendar24.jpg

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collect

collect

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collect

collect

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icon_si_foot.jpg

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41 ms

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make-on.png

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64 ms

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63 ms

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63 ms

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63 ms

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77 ms

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Accessibility Review

xrtpub.harvard.edu accessibility score

92

Accessibility Issues

Contrast

These are opportunities to improve the legibility of your content.

Impact

Issue

High

Background and foreground colors do not have a sufficient contrast ratio.

Internationalization and localization

These are opportunities to improve the interpretation of your content by users in different locales.

Impact

Issue

High

<html> element does not have a [lang] attribute

Names and labels

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Impact

Issue

High

Links do not have a discernible name

Best Practices

xrtpub.harvard.edu best practices score

50

Areas of Improvement

Trust and Safety

Impact

Issue

High

Does not use HTTPS

High

Includes front-end JavaScript libraries with known security vulnerabilities

Low

Ensure CSP is effective against XSS attacks

User Experience

Impact

Issue

High

Displays images with incorrect aspect ratio

High

Serves images with low resolution

General

Impact

Issue

Low

Detected JavaScript libraries

High

Browser errors were logged to the console

High

Page has valid source maps

High

Issues were logged in the Issues panel in Chrome Devtools

SEO Factors

xrtpub.harvard.edu SEO score

78

Search Engine Optimization Advices

Content Best Practices

Format your HTML in a way that enables crawlers to better understand your app’s content.

Impact

Issue

High

Links do not have descriptive text

Mobile Friendly

Make sure your pages are mobile friendly so users don’t have to pinch or zoom in order to read the content pages. [Learn more](https://developers.google.com/search/mobile-sites/).

Impact

Issue

High

Document uses legible font sizes

High

Tap targets are not sized appropriately

Language and Encoding

  • Language Detected

    N/A

  • Language Claimed

    N/A

  • Encoding

    UTF-8

Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise Xrtpub.harvard.edu can be misinterpreted by Google and other search engines. Unfortunately we cannot identify language used on the page (probably there is a mix of languages, too little text or something else) and no language is claimed in <html> or <meta> tags either. Our system also found out that Xrtpub.harvard.edu main page’s claimed encoding is utf-8. Use of this encoding format is the best practice as the main page visitors from all over the world won’t have any issues with symbol transcription.

Social Sharing Optimization

xrtpub.harvard.edu

Open Graph description is not detected on the main page of Xrtpub Harvard. Lack of Open Graph description can be counter-productive for their social media presence, as such a description allows converting a website homepage (or other pages) into good-looking, rich and well-structured posts, when it is being shared on Facebook and other social media. For example, adding the following code snippet into HTML <head> tag will help to represent this web page correctly in social networks: